Intel Lindenhurst Xeon DP Platform Discussion

Steve from Hexus writes "Hexus.net has a article looking at Intel's latest Xeon platform: Lindenhurst, discussing the Paxville dual-core processor, E7520 core-logic, where it could go right for Intel, and where it could all go wrong." From the article: "If you're I/O bound by your threads in any way, you can hit problems (all threads touch the MCH, then there's a 266MiB/sec bus link to the I/O processors to cross, then the data hits disks or network hardware). If you're memory subsystem bound in any way, especially on a majority of compute threads, performance is likely gone. There's just too much resource sharing for it to all conceivably work well, especially compared to Opteron. I can forsee many a scenario where dual-core Opteron will give Paxville Xeon DP a beating."

Comments

Men in Black?

[schon]

there's a 266MiB/sec bus link

Wow - that's a *LOT* of Tommy Lee Joneses and Will Smiths!

Re:Men in Black?

[swillden]

Wow - that's a *LOT* of Tommy Lee Joneses and Will Smiths!

:-)

Looking past the joke, for anyone who may be wondering why that 'i' is there, they're just being accurate. "MiB" is the abbreviation for "mebibyte", which is 2^20 bytes. The more "common" notation, "MB", is the abbreviation for "megabyte", which is 10^6 bytes.

The terms "gibibyte", "mebibyte", "kibibyte", etc. were defined in 1998 by the IEC to disambiguate "megabyte", etc. The "giga", "mega", "kilo" prefixes from the SI units have always referred to powers of 10. With the advent of computers, it became convenient to use them to refer to powers of two that are close to powers of 10. So, "kilo" was used to mean 1024, "mega" was used to mean 1048576 and "giga" was used for 1073741824. The context was generally sufficient to disambiguate those usages from the standard powers-of-ten usages. Basically, everyone figured that if you were talking about computers, the prefixes referred to powers of two.

But there are plenty of computer-related contexts where the prefixes have their traditional meanings. Hard disk drive storage sizes, for example, are measured with powers of 10 by drive manufacturers, but file systems generally use binary prefixes This is why your 80GB drive shows up as only 74.5GB "formatted". It's not that lots of space is wasted by the formatting; the issue is that 80*10^9/2^30=74.5. The two measurements are using different units. Data rates are also traditionally specified in powers of 10. RAM sizes are powers of two.

So, to disambiguate the prefixes while not disturbing the traditional meanings, the IEC coined a new set of binary prefixes, along with corresponding abbreviations. The new prefixes all end in "bi", for "binary".

gooooo Intel!

[tomstdenis]

cost 3 times as much as the 820D ... it's a copy of the 820D ... see where I'm going with this?

The dual-core intels may cost half as much as the dual core Athlon64s but they still suck twice as bad. What you save in initial purchase cost you lose in electricity bills and time doing work.

The fact they're STILL making Netburst based processors just sickens me. Give it up already and go P6 or something new. I mean if they put half the money they put into the netburst into the P6 designs of late they'd already have a 2.5Ghz P6 core that would give AMD a run for their money.

I think the cats out of the bag for the most part. And not like you're gonna sell a lot of dual-core based Dells to grandma so she can write emails.

Times like this make me feel proud I'm an AMD whore :-)

Tom

I/O Bound via DP

[faqmaster]

Yep, I'd say that if both her input and her output are busy, she's DP.*

*See, kids? This is why you should avoid too much pr0n, it just totally warps your mind.

Re:Regarding the electricity consumption...

[tomstdenis]

Better though is that the D series can only clock down to 2.8Ghz whereas the AMD64s can go down to around 1Ghz [depending on your part]. Clocking from 3.2Ghz to 2.8Ghz doesn't save you that much power [maybe 10W at most ...].

My AMDX2 is sitting here running Linux and is clocked when idle to 1Ghz ... at 32C with a copper heatsink. The processor draws around 20-30W when idle compared to the Intel processors which draw nearly double that at idle.

In no way is a Netburst based processor a wise decision over the offerings of AMD.

Tom

Slashdot posts anything these days

[tayhimself]

GamePC has real benchmarks showing the Paxville Xeons getting blown away by Opterons. http://www.gamepc.com/labs/view_content.asp?id=pax ville&page=1&cookie_test=1/

The Hexus article is just a summary of their results along with several inaccuracies.

If you're I/O bound by your threads in any way, you can hit problems (all threads touch the MCH, then there's a 266MiB/sec bus link to the I/O processors to cross, then the data hits disks or network hardware). If you're memory subsystem bound in any way, especially on a majority of compute threads, performance is likely gone.

This is misleading. First off, the MCH is a 6.4 GB/s link so I dont understand how it could bottleneck I/O even if you're compute bound. The 266 MB/s IO bus is for legacy peripherals (USB/serial/SATA). Considering SATA-I (what the ICH5R supports) is 150 MB/s per channel, and USB is 400 Mb/s I cant see how this is a big problem. If you want fast (SCSI/FibreChannel/SATA-OII HW raid) disks and network, there are PCI-X 64bit and PCIe x4, x8 slots that you can have your important I/O subsystem hanging off of.

Here is a link to the intel datasheets for the chipsets which shows 3 x8 PCIe interfaces for the 7520 and 1 for the 7320. http://www.intel.com/products/chipsets/E7520_E7320 /

All that being said, the CPU itself is a dog.

Re:FSB @ 200Mhz quad piped?

[Lonewolf666]

For a single CPU, the quad piped 200Mhz FSB does fine. It can fully utilize two channels of DDR 400 RAM, which is the standard on the better desktop mainboards. A single AMD CPU does not better.
Things are different with multiprocessor setups:
Here each Opteron has its own memory interface, while the Xeons have to share one FSB. As a result, the total Opteron memory bandwith is proportional to the number of sockets. Total Xeon bandwith does not grow with more sockets.
This does show up heavily in reviews of 2-processor machines, expect it to be worse in 4- and 8-way-systems.