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G5 vs Opteron, Finally
metfoo writes "It's been months since the G5 and Opterons have been available for purchase. When the G5 systems were first released, many Mac bashers and AMD nuts discredited the G5's performance. They always ended their comments with 'Wait until its compared to an Opteron, then we'll talk.' Well, it's finally time to talk. Barefeats has posted an article comparing the two systems. The G5 line was compared to a Dual 2GHz Opteron and the results are impressive. In gaming, the Opteron system proved to be superior, which is partly due to the superior 9800XT over the base Radeon 9800. The G5 spanks the Opteron in many of the non-gaming tests, except for the Photoshop tests."
same could be said for the G5, as OS X is not fully 64-bit yet, and neither are many of the programs (with the exception of a few high-level apps, like Photoshop, etc)
Viva La Revolucion! Buy a Mac!
had feature called "The Race Is On" by Jonathan Seef. The comparison was between G5 and PC's with opteron. The PCs seemed to fare better in most of the tests (photoshop, word, quake, premiere, mp3-encoding, mpeg-2 encoding). Mac seemed to be better only with the DVD creation. By the way, I use Powerbook G4. Anyone's got a link for the article ?
Science as a way of life.
Except for nVidia cards, which have always had excellent OpenGL drivers, D3D renders faster than OGL on practically all current consumer level 3D hardware for Windows. Even on the nVidia hardware the speed difference is practically negligble.
First, lets examine the statement The G5 spanks the Opteron in many of the non-gaming tests, except for the Photoshop tests. I see five tests in this review, and there are two wins for G5, two wins for Opteron, and one tie. So I really don't see either chip spanking the other. On the second page Opteron wins two, G5 wins one.
Second, the configuration notes section was pathetic. It doesn't really give a very good description of the real configuration of the systems. Anyone that views benchmarks regularly knows that the devil is in the details. Still, this is equally a problem for Opteron and G5.
Third, I wonder what kind of comparison is really valid. Anyone familiar with the AMD/Intel world knows that you can't just grab two 2Ghz chips and run them head to head. The architectures are not the same, it wouldn't be a valid comparison. So with two entirely different ISAs, what chips should be run head to head? The only obvious comparison would be each manufacturer's fastest...in this case I believe the 2GHz G5 is Apple's current fastest, but AMD does have a 2.2Ghz part that is available (see pricewatch) and that wasn't tested.
Lastly, let me address the importance of compilation. I can't speak for G5, but you would get a substantial boost in performance on most applications just with a recompile for AMD64 chips. This is because Opterons have 32 GPRs instead of 16, which can make a big difference (especially in multimedia apps like photoshop). Obviously these products aren't commercially available, but people should be aware that a substantial performance boost for AMD64 could come just from optimized releases of software once it reaches a wide enough audience to make it worthwhile for software vendors.
I guess this has turned more into a "notes about AMD64 architecture" post than anything else. It looks to me like this review is interesting but doesn't really settle much. Both Opteron and G5 performed well.
The key difference is that the opteron is /faster/ in 64-bit mode. There are more registers. The same is not true of a G5. OSX doesn't "break up" instructions - instructions are instructions. OSes don't interpret each one. 32-bit windows on opteron just uses 32-bit instructions, just like 32-bit darwin on a G5. Photoshop is not a 64-bit app in the case of OS X IIRC - it uses a 64-bit math library as its G5 optimization. This is fine and works. As I mentioned in another post, darwin can't run "64-bit apps" yet, because there are no 64-bit interfaces to system calls (think about it - if the kernel expects a 32-bit FILE * and you send it a 64-bit one, you're going to have trouble doing I/O). I think I missed something with what you said there. The main 64-bit part of darwin is the math library since they can throw some 64-bit ASM in there plus code to convert back-and-forth to the 32-bit bindings.
Are the moderators on crack? That's not informative, it's wrong!
The only "piece" of OSX that is 64 bit is the memory access - to allow a G5 to use up to 8 GB of ram.
No, the math libraries and kernel support 64 bit goodness too. While the G5 chip is fully 64 bit, OSX is taking each 64 bit instruction (from 64 bit apps like Photoshop, for example) and breaking it into two 32 bit instructions which it sends one after the other to the CPU.
No, it runs as a single 64 bit instruction through the chip!IBM is working to provide Apple with a much optimized PPC970 compiler tailored for the G5 - this is expected to give a large performance gain for this platform.
This I agree with, in fact it should be pointed out that the compiler is available now as a beta on IBM's web site.
there is no emulation in either chip, it is all native.
I am the Alpha and the Omega-3
On the latest Top500 list Virginia Tech's Mac cluster is number 3 with 2200 2GHz G5 processors, and Los Alamos National Laboratorys machine, with 2816 2 GHz Opteron processors is number 5.. I didn't look at the topology, or connection medium, but I am certain that the Mac cluster was cheaper, and is faster running the SAME benchmarks...
Well I dont trust the new (pro mac?) benchmarks either. But those first PC World benchmarks were a joke. Id spend time writing up an articulate reply but others have already done that the first time these benchmarks were posted. so here you go:
8 515
http://slashdot.org/comments.pl?sid=82342&cid=721
--aiee
There is no breaking down of instructions as you mention - there is an extended instruction set which is either available or not on the PPC (so PPC processors which support 64 bit instructions support the full instruction set, whilst the 32 bit processors throw an illegal instruction).
The measure of the processor 'bitness' is when addressing memory, whether you are limited to a 32 or 64 bit address space. In effect the size of a pointer will tell you. Now the impact of moving to a 64 bit address space is usually detrimental to the speed of the application (I would expect that the G5 will be slower in 64 bit mode) due to the increased memory bandwidth required (if pointers are wider, you need more stack/memory to store them, so you have, say, a 10% increase in memory requirement for an application). If I remember correctly, the HP PA RISC systems were slower running 64 bit code than 32 bit. I'm thinking back a couple of years here, so it may be different for the latest generation of their processors.
It isn't all bad for the Opteron though - the instruction set has been altered to provide more processor registers. This may mean the compiler can do a better job of optimising code, reducing the number of load/store instructions, so increasing the IPC.
So, just don't assume that if the Opteron gets a performance benefit from 64 bit code, so will the G5. As other people have mentioned, you need to test both with a 64 bit OS to really know the results - extrapolating won't get you the answers.
Your comment about the IBM compiler is spot on. With any luck the IBM changes will make it into the gcc code for other non-apple PPC platforms.
I don't know if the author of the article was just trying to make the mac look cheaper, or if they just weren't looking very hard (I suspect the latter), but they could have EASILY shaved $82 off the cost of the Opteron system and got 1394b support for free too boot!
For some reason they configured the Opteron with an add-in Serial ATA RAID controller, supposedly in order to better match the configuration of the Mac (which doesn't support RAID, but I digress). This added $117 to the price. However they completely ignored the motherboard upgrade option that added SATA support (no RAID) and 1394b support together for only $35.
They could also have shaved another $37 off the price by using a software modem instead of a hardware modem (though the HW modem might be a good idea for Linux users that need dial-up) or $72 off the price by not including a modem at all for those of us with broadband connections.
In the end though, the Mac is still a bit cheaper. Macs are not expensive for what you get, the problem is that you don't have much choice but to get top-end. To price out a dual-processor Opteron with similar specs to a dual-processor Mac, you'll be easily over $3000 and possibly up closer to the $3938 of the Xi computer system. However, if you don't need all those features you can easily configure yourself an Athlon64 system for SIGNIFICANTLY less.
I have absolutely no need for a modem (got an old external kicking around in case of emergancies) and have never owned any 1394b devices. Therefore, if I were configuring a PC for myself I would never bother adding either of those two options. I might also configure a cheaper video card and I probably wouldn't bother with a DVD-RW drive, though I would prefer to have two optical drives (one CD-RW and one DVD). These are all easy options on most PC configurations, but often they aren't on Mac configurations. Simply put, you have more choices on PC configurations than on Macs. If you desired setup matches that of a Mac closely, then they often offer good value for your money. If not, then they can be quite expensive for what you want.
Actually, the G5 is Apples Pro Line. Their consumer line consists of the iBook, iMac, and eMac. Their Pro line consists of the PoweBook and Power Mac. Maybe the naming gives it away too... POWER Mac, POWER Book.