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Mixing Gigabit, Copper, and Linux
iampgray writes: "With copper-based gigabit cards selling for less than $36 these days, what kind of performance can you expect -- especially in the often-overlooked Linux market? We sought out to test exactly what you could expect from copper-based gigabit solutoins for the desktop interface through the cluster-targeted products. Name brands and off-brands were put through the wringer. How'd they fare? Interesting results to say the least."
Are we even to the point when a normal PC could handle Gigabyte? And if so, why not use optical? I mean, saying I've got a fiber optic home network is a lot cooler then saying I've got a gigabyte eth home network. I mean to a geek, (to anyone else, that would just be lame... er...)
How much more expensive is the optical stuff for GigE? I'm mostly using optical audio connections from my home sterio, and that's not to much money
autopr0n is like, down and stuff.
I checked out the cards, and yes you can get them cheap, but what about switches? You figure they're still uber-pricey too, right?
:)
Nope... apparently Pricewatch.com has D-Link 8-port 10/100/1000baseT auto-detect switches listed for under $150! (I've been most happy with my D-Link DI-804 Router/firewall/switch for $79.)
Is this the normal "cheaper as tech gets more widespread and easier to manufacture," and do you think maybe Apple making gigabit ethernet a standard feature had something to do with it?
SlashSigTheorem: Humorous, Political, Critical, Constructive- If you have a
How'd they fare?
/. effect.
/.ed to oblivion? That's not interestng, that's anti-climatic - I know what happens before I get to the story. Oh well...
Not terribly well against the
Interesting results to say the least.
Lessee, a story about increasing bandwidth on a server
Soko
"Depression is merely anger without enthusiasm." - Anonymous
Could you post a summary? That must be about the fastest /.-ing I've seen. What'd that take, about 5 minutes?
D-Link DGE-500T
.0002 seconds.
/((192.21+172.21) / 2) = $.25>
.0002 seconds.
.0002 seconds on both test platforms.
D-Link DGE-500T was the first of the gigabit cards tested. This card is based on SMC's dp83820 chipset and is designed for a 32bit bus. The chipset in this card turned out performance nearly identical to the two Ark cards and the GigaNIX cards tested in our test suite, since all utilize the dp83820 chipset from SMC. The Linux driver used was the ns83820 as included in the 2.4.17 kernel. Latency on both platforms was
Peak throughput while operated in a 32bit bus was 192.21 Mbps. This was achieved in the Dell systems. The Athlon systems only obtained a peak of 172.21 Mbps when these cards were inserted into the 32-bit bus. Both systems show a slight drop in throughput but eventually level out. Peak throughput while operated in a 64bit bus running at 33Mhz was 315.96 Mbps.
When the bus was jumpered to autoselect 66/33Mhz, the performance increase was negligible. Peak throughput was 316.40 Mbps. Comparing the plots of the 66Mhz and 33Mhz run reveals that they are essentially identical.
For complete testing results, click here.
Price: $45
The cost per Mbps is as follows:
32bit 33Mhz: $45
64bit 33Mhz: $45 / 315.96 = $.14
64bit 66Mhz: $45 / 316.40 = $.14
Ark Soho-GA2500T
The Ark Soho-GA2500T is also a 32-bit PCI card design. Like the D-Link DGE-500T and the Asante GigaNIX cards, this card is based on the SMC dp83820 chipset. With that in mind the performance was estimated to be close to the D-Link DGE500T. The driver used was the generic ns83820 included the 2.4.17 kernel. The latency for both test systems was
The peak throughput achieved while in a 32bit 33Mhz bus was in the Dell system: 192.62 Mbps. While the Athlon system in the same bus setup only reached 172.19 Mbps. As before, there is a performance drop at the 1Kb and 5-10Kb packet sizes.
Peak throughput while operated in a 64bit bus running at 33Mhz was 610.83 Mbps and 609.98 Mbps when running at 66Mhz respectively. As with the Soho-GA2000T, there is no noticeable difference between a 33Mhz and a 66Mhz bus.
For complete testing results, click here.
Price: $44
The cost per Mbps is as follows:
32bit 33Mhz: $44 / ((192.62+172.19) / 2) = $.24
64bit 33Mhz: $44 / 610.83 = $.07
64bit 66Mhz: $44 / 609.98 = $.07
Ark Soho-GA2000T
Our transition into cards designed for a 64-bit PCI bus began with the Ark Soho-GA2000T. Like it's 32-bit counterpart, this card was designed around the ns83820 chipset, which will allow us to examine the performance benefits, if any, in moving from a 32-bit As
Designed to run in a 64bit 66Mhz slot, this card is backwards compatible to 32bit and 33Mhz slots. This card is based off of SMC's dp83820 chipset so performance was expected to be similar to the DGE500T and the Soho-GA2500T. The driver used was the generic ns83820 included in the 2.4.17 kernel. Latency was
Peak throughput for a 32bit 33Mhz slot was 189.93 Mbps in the Dell system. The Athlons were only able to reach 172.26 Mbps.
Peak throughput for 64bit 33Mhz was 665.06 Mbps with an MTU of 6000. Peak throughput while running at 66Mhz was 640.60 Mbps. With the exception of the 6000MTU tests, there is no noticeable difference between bus speeds of 33 and 66Mhz.
For complete testing results, click here.
Price: $69
The cost per Mbps is as follows:
32bit 33Mhz: $69 / ((172.26+189.93)/2) = $.38
64bit 33Mhz: $69 / 665.06 = $.10
64bit 66Mhz: $69 / 640.60 = $.11
Mutually Exclusive? Nope, just limited range. Fiber can go 1000km or more.
Still, sometimes you only want to go a few feet between two servers or something and there you can't really argue with the price.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"Just fyi, Macintosh 1000BaseT ethernet controllers go directly to the memory controller, bypassing PCI altogether..
Care about electronic freedom? Consider donating to the EFF!
Stay away from cards that don't have PXE and cards in which the driver won't compile into the kernel (as opposed to a module) if you plan to do easy installations or mount root off the network. In other words, stay away from Netgear and some 3Com cards (I haven't tested others), and play it safe with Intel.
Well, check out the docs first off. It's hard to get much out of GBit, since most of the utilities don't call the socket open with properly sized buffers/window/whatever.
/* 8192 */
I set up optical gigabit for some NAS type things at work, and out of the box, GBit performed maybe 30% better than 100 Mbit. We are talking about 110Mbit peaks, compared to 80Mbit peaks with 100Mbit switched.
Setting the MTU to 6144 (max that I could set it to with the ns83820.o) I started to get peaks around 300Mbit/sec.
I tried recompiling the module for higher limits, since in the source it has:
#define RX_BUF_SIZE 6144
But if I put in 8192, or 9000 like I wanted it to be, it would crask or lock up.
Anyway, it's not trivial to get good performance out of GBit, and definitely don't expect anywhere near 10X gain.
I've had enough abrasive sigs. Kittens are cute and fuzzy.
Comparisons and Observations
In this section, we compare performance differences between cards in like environments , provide some general performance observations, and examine the cost per megabit as determined by the operating environment.
Head-to-head throughput results
While the results obtained in this study clearly show that peak performance is not a complete indicator of peak performance, in this section we examine the peak performance results amongst all cards under common environments.
32-bit, 33MHz PCI Bus, 1500 MTU
64-bit, 33MHz PCI Bus, 1500 MTU
64-bit, 66MHz PCI Bus, 1500 MTU
64-bit, 33MHz PCI Bus, 3000 MTU
64-bit, 66MHz PCI bus, 3000 MTU
64-bit, 33MHz PCI bus, 4000 MTU
64-bit, 66MHz PCI bus, 4000 MTU
64-bit, 33MHz PCI bus, 6000 MTU
64-bit, 66MHz PCI bus, 6000 MTU
64-bit, 33MHz PCI bus, 9000 MTU (Note: Drivers for the dp83820 chipset were limited to around 6000 MTU)
64-bit, 66MHz PCI bus, 9000 MTU (Note: Drivers for the dp83820 chipset were limited to around 6000 MTU)
General Observations
Of the eight cards tested, the clear performance champion was the SK9821 with regard to throughput and consistency. The 3Com 3c996BT has a modest price tag and respectable performance for the entry-level server configuration. If price per megabit is the main concern, the Ark Soho-GA-2500T has the lowest cost per Mbps, making it a viable solution for entry-level systems requiring higher throughput than fast ethernet.
The D-Link DGE500T and the Soho-GA2500T show nearly identical peaks, which is to be expected since the drivers and the chipsets were the same.
The 3Com 3C996BT has results when compared to the 64-bit 33MHz results were surprising inasmuch as these cards showed better performance at 33MHz bus than at the higher 66MHz bus.
Of all of the cards tested, the Intel E1000 TX proved to be comparable to the comparable to the Asante GigaNIX card in peak performance, but the erratic overall performance proved too much to overcome.
In referring to the Complete Test Results sections for the 3C996BT and the SK9821 cards, one sees a very consistent and smooth transition to the peak throughput of the cards over the complete range of packet sizes.
Some general comparisons that can be derived from the above results include the notion of ''cost per peak megabit. Depending upon the environment that the network device is to be installed, the cost per peak megabit varies greatly. For example, if one would wish to upgrade their P-III-based desktop system with a 32-bit, 33MHz PCI, the GA25000T is the clear cost-effective solution, but would not be able to provide throughput at the level of the 3Com 3C996BT.
In an HPC environment, where sustained throughput is critical and the switch is capable of Jumbo frames, the SK9821 would be the best performer. In light of gigabit switching hardware that lacks Jumbo Frame support, a comparison of the 1500MTU results shows the SK9821 is still a viable choice, as is the 3Com 3C996BT which provides a more cost-effective solution.
Paul Gray
323 Wright Hall
University of Northern Iowa
apparently Pricewatch.com has D-Link 8-port 10/100/1000baseT auto-detect switches listed for under $150!
;).
These are for 8x100-base-T with a gigabit uplink. I researched this a while ago, when speccing out my dream network
The cheapest full-gigabit switch D-link sells is about $1500.
I knew that actualy, and even flamed someone for typing "MB" when he meant "Mb". Oh well...
autopr0n is like, down and stuff.
you, sir, are taking a huge slurp from the karma tit today. Congratulations to you! Cheerio.
Wow, you are paying way to much. a 12ft optical cable I had used to connect my PC to my sound system broke a couple of days ago, and I thought it was gonna cost me $40 to replace it. Radio shack sold em for $44, but sears had a 12footer for just $20.
autopr0n is like, down and stuff.
The cards are well priced for home use, and CAT5E cabling is cheap too. The problem with gigabit ethernet is not the cards, it is the lack of switches or even plain hubs at an affordable price point. There are lots of switches out there with a single gigabit port, but even those are a couple of hundred dollars. If you want multiple gigabit ports, you are looking at more than $600 for the bottom rung products.
When information is power, privacy is freedom.
Someone needs to learn the difference between a gigabit and a gigabyte....
Doing Math we can calculate that a full gigabit of transfer is 125 Megabytes a second. I think this is possible with high end hard drive technologies like SCSI RAID and speeds like this will probably show up in the desktop in a few years.
And, of course, not all data has to be written on Hard Drives. You could have a router or switch that will pass along a gigabit of packets a seconds but it certainly doesn't write them to the hard drive. You could for example but in a Gigabit Ethernet connection between two nearby buildings.
Tim
Omnia vestra castrorum habetur nobis.
and I took Networking from him last semester. He did a preliminary demo for the class, and I think that on the 32 bit PCI Gigabit cards, the effective throughput was around 250Mbps. Of course, the PCI bus was the limitation.
A 64 bit PCI card was getting significantly higher throughput. I don't remember the exact numbers, but it was much closer to 1000Mbps (maybe 800?).
I got about 32 MByte/s one-way with `ttcp` [UDP] between a 1.2GHz K7 and 2*500 Celeron (BP-6) through a plain crossover cable.
Not bad, but only 25% of wirespeed (125 MByte/sec). I figured the main limit was the PCI bus, which would only burst at 133 MByte/s, and I strongly suspected that the bursts were too short to achieve anything like this speed. I have yet to play with the PCI latency timer.
One thing for sure -- it isn't the CPU speed or Linux network stacks. The K7 will run both ends of ttcp through the localhost loopback at 570 MByte/s, and the BP6 around 200 MB/s.
Get a cheaper brand of cable, something tells me you really won't be able to hear the difference. All that regardless, the kind of fibre used for eithernet is not nearly so expensive. I can get 12-strand (6 single mode, 6 multi mode) fibre at around $1.00-$1.50/foot. That has enough for 6 different connections, three of them single mode (which costs more). For a short run of premade multi-mode fibre with the ends on it I'd think you shouldn't pay much more than $1/foot and perhaps less. At a length of 50 metres it should be around $0.50/foot.
IF Eithernet fibre was as expensive as you suggest, the university I work at would be bankrupt. Just last week I laid about 50 30-metre patch cables in a closet. This is not to mention the thousands already in place and the millions of metres of fibre that connects the buildings together.
Anybody out there running Linux on a G4 using 1000BaseT ethernet?
There was another review of GigE performance in the IEEE Network Magazine last year.
Are there any NICs using the AGP? Not many boards have 64bit PCI yet, let alone PCI-X, but every board has an AGP slot. This would be great for cheap 1U cluster nodes, with an appropriate riser card of course.
Did you know you can fertilize your lawn with used motor oil?
Wow, that is the best fucking karma whoring mess I've ever seen. Drink it up dude...
SIG: HUP
First, you can't just stick a gigabit card in a machine and expect it to work at full capacity. The basic design of ethernet was not really designed for gigabit speeds, but we've managed to squeeze it out - barely.
With 10 mbit cards, having the card generate an interrupt with ever incoming frame wasn't too bad. And on 100-mbit, it's still managable - but at a full gigabit, it really, really starts to bog down the machine. Some cards get around that by using interrupt coalescing, where they buffer up a few frames before they trigger an interrupt. That has a drawback, though: It increases latency. The trade-off has to be at some point, and not choosing the RIGHT point can affect either throughput or latency.
Furthermore, to get the full benefit out of your card, you generally need to enable jumbo-frames on both the card and the switch - and of course, your switch has to support that feature.
To make matters even worse, you can't always pump out (or receive) a full gigabit in any other than testing situations. Say you're receiving a large incoming file via FTP, NFS, or the protocol of your choice. Can your machine *really* write data to the disk at over 100 megabytes per second? And if it can, can it really handle both receiving a gigabit from the card, processing it, and writing the gigabit out to the disk? Unless you've got a very large amount of money in the machine, it probably won't.
steve
Oh, you're not stuck, you're just unable to let go of the onion rings.
Technically we are both "right". However, when you use the term "bits" you mean binary digits. emphasize binary. We are not using base 10, but base 2.
The Free On-line Dictionary of Computing (13 Mar 01)
prefix
1. The standard metric prefixes used in the SI
(Syst`eme International) conventions for scientific
measurement. With units of time or things that come in powers
of 10, such as money, they retain their usual meanings of
multiplication by powers of 1000 = 10^3. When used with bytes
or other things that naturally come in powers of 2, they
usually denote multiplication by powers of 1024 = 2^(10).
Here are the SI magnifying prefixes, along with the
corresponding binary interpretations in common use:
prefix abr decimal binary
yocto- 1000^-8
zepto- 1000^-7
atto- 1000^-6
femto- f 1000^-5
pico- p 1000^-4
nano- n 1000^-3
micro- * 1000^-2 * Abbreviation: Greek mu
milli- m 1000^-1
kilo- k 1000^1 1024^1 = 2^10 = 1,024
mega- M 1000^2 1024^2 = 2^20 = 1,048,576
giga- G 1000^3 1024^3 = 2^30 = 1,073,741,824
tera- T 1000^4 1024^4 = 2^40 = 1,099,511,627,776
peta- 1000^5 1024^5 = 2^50 = 1,125,899,906,842,624
exa- 1000^6 1024^6 = 2^60 = 1,152,921,504,606,846,976
zetta- 1000^7 1024^7 = 2^70 = 1,180,591,620,717,411,303,424
yotta- 1000^8 1024^8 = 2^80 = 1,208,925,819,614,629,174,706,176
------
BINARY BINARY BINARY! WE USE BINARY! Take a look to the right under "mega". mega- M 1000^2 1024^2 = 2^20 = 1,048,576. Therefor, 2^30 / 2^20 = 2^10 = 1024 megabits in 1 gigabit.
Now, what part of that dont you understand?
Buying a Dell computer is equivalent to dropping the soap in a prison shower.
IMHO, the 'intelligent descision' should just fall out of how it's all designed instead of being an explicit part of the low level design.
Need a Python, C++, Unix, Linux develop
Gigabit optical network cards a only a little
over a 100$ now, are full duplex and faster
than copper in most cases. We've just installed
4 Dual Athlon 2000MP linux boxes, with gigabit
optical cards, pretty damn fast as you can
imagine.
Wow. That makes any analysis tough, when performance measures fail to satisfy the Reflexive Property!
Brian
The much nicer interface would be to have a living room box join my ethernet LAN. The box would just receive uncompressed audio and video from the computer over gig ethernet. That way, all the decompressing would be done by the fancy CPU in my bedroom, and the box would not become obsolete when new/more CPU-intensive codecs came out. (Because the alternative is, of course, to have the box do the decompression, but I don't like that.) Somebody please make one of these (or explain why it would be a bad idea).
For those of you who don't know how this works, here's a bit of a primer: basically, you set the port on your big data center grade switch to "trunk" and then you enable 802.1q on your Linux box. Then you don't just have one Ethernet interface with one address --- you have up to 4096 virtual ones, each on its own VLAN and each with an IP address that's valid on that VLAN. So you'd have eth0.1, eth0.2, eth0.3, etc... each talking to the machines on that VLAN.
Once you've got that running, you can do all sorts of neat stuff, including:
As you can see, it's limited only by your imagination. And with that much stuff potentially running through the box, you're going to need that 1 Gbps of speed. Happy hacking!
Tired of FB/Google censorship? Visit UNCENSORED!
So I also ran a netpipe test to see what it thought of my NICs.
It gives you a NetPIPE.out. According to the man page, they contain: "time to transfer the block, bits per second, bits in block, bytes in block, and variance."
First of all, the manpage is wrong because the second column gives a number much closer to megabits per second, and after numerical verification, I found that it's giving the value of 1024*1024 bits per second and not 1000*1000 bits per second.
In NIC-talk, when we say gigabit, we mean 1000,000,000 bits, not 1000*1024*1024 bits.
So when benchmarking your gigabit network card with netpipe, please remember that you're looking at speed results "1024*1024"-megabits, so your NIC is really only 953.6 megabits, which immediately gives a much better insight into the speed achieved by the Syskonnect card.
--- Hindsight is 20/20, but walking backwards is not the answer.
Pretend I have 3 cheap Athlon based systems in one building. Assume one is acting as a server, and the other two are clients that aren't talking to each other. Because these are the cheaper cards, I only expect 300Mbps when one client is active. What happens when both clients are active?
Ideally, throughput would be no worse than 150Mbps/per card. I suspect it would be much worse.
If multiple cards did work well, then you could buy 6 cards to directly connect 3 machines. Much cheaper than 3 cards and a GigE switch.
I think I'll have to wait until even cheap machines have 64bit/66Mhz PCI busses. I know I'll have to wait until I get all my machines into one building.
Have you ever heard of cable testers?
Sheesh - a TDMA for fiber can tell you not only the quality of the cable and terminations, but also the distance to any faults!
(Believe me, I've got a OmniScanner for copper and I'm itching for Fiber - i just can't justify the cost yet. Troubleshooting cable run problems is really a breeze! And no guessing either. If the "Joes" you got installing fiber don't give you full certification results, you've not done your job in setting the specs for the job. And if your cable is getting damaged after install, either the cable didn't get installed right (protected runs etc) or you've got very careless people running around where they shouldn't.
Fiber is more difficult, but that's really because it hasn't reached critical mass. Once it starts getting installed in higher quantities, we'll see easy termination kits (there are some already).
Cheers!
I'd be happy with an 8 + 2 switch from someone-- i.e. 8 10/100 ports with 2 10/100/1000 ports for my main file sharing boxen (and I imagine these would be a hit at LAN parties, so the server running the game could have a gigabit connect to the switch, allowing most of the 10/100 connections to saturate it with updates (and vice versa)). The trend of hardware makers (Netgear has done this too, FS309T is an 8 port 10/100 with a SINGLE 10/100/1000 copper gigabit port) to make these 8 + 1 solutions just sucks (since you can't really test the faster speed of gigabit with JUST one port).
Of course in a perfect world, I'd agree that 8 port gigabit switches being $200 or less would be about near perfect, especially if higher port counts weren't unrealistically high.
All I know about Bush is I had a good job when Clinton was president.
Also check out R. It has, IMHO, somewhat more advanced graphing stuff than gnuplot.
There must be something wrong with the graphs for the e1000 packet size vs. throughput plot, I believe the axis are reversed.-
Also Intel acknowledges that their e1000 adapter have driver issues under linux. This text is from: ftp://aiedownload.intel.com/df-support/2897/ENG/re adme.txt
Known Issues
============
Driver Hangs Under Heavy Traffic Loads
Intel is aware that previously released e1000 drivers may hang under very
specific types of heavy traffic loads. This version includes a workaround
that resets the adapter automatically if a hang condition is detected. This
workaround ensures network traffic flow is not affected when a hang occurs.
This is for the driver verion 4.1.7, released 3/23/2002 (ie. quite new). Older versions had even bigger problems. This might explain why the Intel adapter does so bad in this test. I wish that Intel gets a clue and releases all card specs and GPLs the existing driver so that a true (stable) open source driver could be written and included in the linux kernel. I think the hardware is OK, but the drivers sucks.
RFC1925
Does Intel's desktop cards support PXE (or rather, have the correct support so as not to be lumped in with Netgear's cards (bleh.. when I first got into networking I bought some Netgear cards because I had such great success with their switches/hubs-- NEVER AGAIN; this is the company that accidentally setup their PCI ID (or whatever it is that allows Win9x to autodetect and load drivers for devices) incorrectly as ANOTHER card, thus allowing Windows to load the WRONG driver for the card-- nightmare!)?
I've had really good experiences with Intel NIC's, and in fact have two Pro 100/S Server Adapters and two Pro/1000 T Server Adapters (the forefather to the newer 'server' class models) for use in my systems-- Intel's driver support is absolutely amazing, and incredibly stable/friendly. The fact that they offer up alternate platform drivers is just another bonus.
All I know about Bush is I had a good job when Clinton was president.
As many have said, Gigabit switches are priced WAY out of proportion to the price of Gigabit NICs.
So how about filling up a cheap PC with cheap NICs and using it as a switch?
Granted as others have said, the PCI bus is a limiting factor. But it will certainly blow away any 100mbit switch.
Another possibility is to put two Gigabit NICs in every machine, and run a daisy chain or even a ring type network.
Sounds like a fun project!
The DLink Gigabit ethernet cards I threw into the small file storage machine that hangs off of my computer don't care what cable you stick in them. As long as the wires come out, it figures out what's the correct 'routing' - crossover or regular.
:P
So does that mean my $99 Gigabit Ethernet Card is at least as special as your $3000 Mac?
I needed gigabit bandwidth at work because I am moving 100GB files.
:). If you can afford to do power cycling once and a while and it's not a buisness server with critical uptime, it's not all bad.. (like for a little renderfarm).
I went on reading about it on the net, on sites like www.3wire.com for example, and to make a long story short, Fiber optic yeilds the best results (obviously) but are way to expensive. Next are some 1000T copper cards that are almost doing the job, but then again, after getting 5 different cards, I can tell you right away that you can have a BIG difference from a board to another.
The best card I've got so far performance-wise are the Intel Pro 1000T-based adapters, with no optimization card to card running netcps, I'd get twice as much speed out than with the Dlink counterpart (DGE500T). They are a bit more expensive, but if you want more than 3x increase over 100Mbits, you need something a tad more expensive.
The other thing is you see card with 70Megs/second bandwidth tests on some websites, with jumbo packets turned on. You need a jumbo-frame capable switch (read: Expensive) to be able to turn that on. The cheapest gigabit switch I've found that could take an aweful lot of load without costing me an arm was the Netgear GS508T, but if you are used to managed switch, that one isn't.
Also you might be tempted to get a Gigabit card as upling with let's say 8 ports @ 100Mbits, that way you won't waste bandwidth to the server and the 8 of them can crunch it. Well good idea on paper but don't get the Dlink DES-1009G, I had to return 2 of them, and the firmware on that thing truely SUCKS. You can't just leave it there and forget it, you need to cycle the power sometimes so it can "read properly" on the ports wether 100 or 10 or half or full duplex. It's miserable and poor performing. It's cheap though
For the Intel pro cards, I got both the workstation and server ones, server being 64bits PCI.
There's one thing you want to consider, if you use Gigabit ethernet, you need also to be able to feed it, 50megs/second on the board requires a drive being able to deliver 50 megs a second to the card, and requires a PCI bus able to take the load as well (remember, it's 50megs x 2 bandwidth on the bus that on pci32/33mhz saturates at 128 but in real world 100).
--- Metamoderating abusive downgraders since my 300th post.
It's used in the Linux kernel, for example:
Linux version 2.4.18 (root@yeti) (gcc version 2.95.4 (Debian prerelease)) #15 Wed Apr 3 02:12:16 AST 2002
hda: 60046560 sectors (30744 MB) w/2048KiB Cache, CHS=29785/32/63
hdc: 25429824 sectors (13020 MB) w/418KiB Cache, CHS=25228/16/63
#define X(x,y) x##y
Peter Cordes ; e-mail: X(peter@cordes ,