Author: Aaron Gordon
Date: 12:35:25 12/02/02
Go up one level in this thread
On December 02, 2002 at 15:12:36, Robert Hyatt wrote: >On December 02, 2002 at 14:48:33, Aaron Gordon wrote: > >>On December 02, 2002 at 10:49:47, Robert Hyatt wrote: >> >>>On December 01, 2002 at 23:13:39, Aaron Gordon wrote: >>> >>>>On December 01, 2002 at 22:19:16, Robert Hyatt wrote: >>>> >>>>>On December 01, 2002 at 12:57:51, Aaron Gordon wrote: >>>>> >>>>>>On December 01, 2002 at 12:28:38, Robert Hyatt wrote: >>>>>> >>>>>>>On December 01, 2002 at 05:03:00, Jorge Pichard wrote: >>>>>>> >>>>>>>>Also a comparison of the new AMD XP 2600+ Vs Intel P4 2.53 Ghz ! >>>>>>>> >>>>>>>>http://www17.tomshardware.com/cpu/02q3/020821/athlonxp-04.html >>>>>>> >>>>>>> >>>>>>>That just highlights what others have said before. AMD has a memory >>>>>>>bottleneck that is hurting them significantly in the war with Intel... >>>>>> >>>>>>Hyatt, it's not nearly as bad as you think. It happens I have a KT333 chipset on >>>>>>an Epox 8K5A2. I'm running "Turbo" settings in the bios (but running CL2.5 >>>>>>instead of CL2(cl2=faster)) and I'm getting 2.5gb/s. >>>>> >>>>>So? That is about 1/4 what the PIV xeon can do. Go to tom's hardware page >>>>>and you'll find some interesting comparisons... >>>> >>>>I have been going to Tomshardware for years now, watching the stuff he's been >>>>saying, stuff he's posting and etc. I haven't seen anything interesting in years >>>>as well. You say the P4 Xeon can do 10gb/s? (2.5x4). I think not. >>> >>>The number I have seen for the 2.8 xeon on the E7501 chipset was about >>>6.5gb/second. I either mis-typed my response or misread your number as >>>1.5, I don't remember which. But the AMDs are not approaching 6+ gb/sec >>>yet in any test I have seen. And on a few of the really memory intensive >>>_real_ applications such as linpack, the fastest intel box has been posting >>>number 3-4x that of AMD... And I'm not talking about overclocked numbers as >>>I ignore those. >>> >>> >>>>The efficiency >>>>on P4's is less than desirable. The 133fsb(533QDR) PC1066 RDRAM P4's can >>>>supposedly do something like 8.5gb/s. Actual bandwidth = 3.2gb/s. Not too >>>>impressive. Around 37% efficiency. As as said in the previous message an Nforce2 >>>>can manage over 3gb/s at over 95% efficiency & with much lower latencies >>> >>>I have looked around and don't see any references to support the above. The >>>2.8xeons are at the top of the bandwidth heap on every chart I have seen. >>>Notice that I am specifically addressing "2.8ghz xeon using the E7500 chipset" >>>as that is the machine I have ordered and that is the machine that I carefully >>>studied on the intel side when making the decision... I had some crafty >>>benchmark data from that machine as well as the recent 2800+ AMD and I made >>>the decision based on performance and nothing else... And before you ask, >>>(a) I didn't do the benchmark tests and (b) I can't reveal the people that >>>did them, but you can probably at least figure out who they work for... Same >>>for my Itanium2 numbers that I have mentioned in the past... But that doesn't >>>mean the numbers are "phoney". Whether the athlon 2800+ dual is faster >>>for another program doesn't matter to me since I work on Crafty. I'm not >>>even sure when the 2800+ will be actually available, but it doesn't matter >>>in the context of what I am doing anyway... >>> >>> >>> >>>> >>>>If you bothered to do any testing yourself you'll find out the P4 isn't what >>>>it's cracked up to be. It's odd to me that you have such a blind confidence in >>>>the P4. You haven't bothered doing any extensive testing on one and you haven't >>>>messed with an Athlon yet you 'feel' the P4 is faster. Why is that? >>>>I can try to believe a Pinto is faster than a Ferrari but it's just not going >>>>happen. :) >>>> >>> >>>I haven't tested on AMD, you are correct. But I _have_ tested on a dual PIV >>>as I said before. And I will have a dual 2.8 here pretty soon (I hope, if >>>the holidays don't cause delays). >>> >>>I don't "feel" anything is faster than anything else. I rely on numbers posted >>>by people here that I trust. Eugene is one, as I doubt anyone knows more about >>>the internals of both processors (from an assembly/optimizing/etc point of view) >>>than he does. So when he posts numbers I listen. And his dual PIV numbers >>>were better than the dual AMD numbers. Others also have the PIV on top of the >>>heap, including Tom's page of course... >>> >>>However, if someone has a dual AMD 2600+ (or whatever they are going to call >>>the chip after admitting their "+" numbers were too optimistic) running linux, >>>we can compare speeds once my machine arrives. That's the way I tend to settle >>>speed disputes. Run the test... If I thought AMD was faster, I'd have bought >>>a dual AMD. If I could have afforded a dual/quad itanium-2 I would have bought >>>that as nothing else is close. If Cray built something in this price range I >>>would have gone that way as well. I try to "follow the performance" and don't >>>have any vendor-specific preferences at all, although I had a couple of very bad >>>AMD experiences in the K5 days, and that did leave a sour taste... But if AMD >>>can take the performance lead, I'd buy. But so far, they've been unable to >>>even think about quad machines... while Intel has had 'em for at least 5+ >>>years. That means they will _always_ be behind by a factor of nearly two or >>>so... >>> >>> >>> >>> >>>> >>>> >>>>>>This just proves once again Tom is a bad reviewer. There's already proof out he >>>>>>faked a Pentium4 review and I have proof he hinders Athlons (by setting their >>>>>>bios settings to the absolute lowest setting). The KT333 set to "turbo" has an >>>>>>efficiency of 94%, this means out of 2.7GB/s max theoretical bandwidth at >>>>>>166fsb(333DDR) it does 2538MB/s. Since mine is CL2.5 I'm only running 90% >>>>>>efficiency (2430mb/s). With Nforce2 boards and running 200+ fsb you can get over >>>>>>3gb/s on an Athlon easily. Same with the Epox 8K9A2. >>>>> >>>>> >>>>>Again, that is _still_ slow compared to the PIV xeon numbers with (say) the >>>>>E7501 chipset... >>>>> >>>>> >>>>> >>>>>> >>>>>>Tom however is managing a horrible 74%. You can do better than this even setting >>>>>>the settings to 'normal'. He has disabled other options to get the benchmarks >>>>>>THAT low. 26% below regular 166fsb(333DDR) scores is pretty bad. >>>>>>Even your average KT266a/333/400 board at 133fsb gets about 2gb/s. >>>>>> >>>>>>About the faked review he did.. it's the "Hot contraband P4-3.6GHz". He used a >>>>>>Pentium4 2GHz CPU and cut&pasted some of the 3's to make it look like a 3.3GHz >>>>>>P4. The picture is STILL on his page. Just go look at that article and save the >>>>>>large P4 picture. Go into an image editing program and go near the bottom where >>>>>>it says "80531PC3.3G0K". Drag a selection box around the second three in that >>>>>>line and copy it, invert the colors and then drag that over the other three. You >>>>>>will see a black box where the colors match EXACTLY. This was a cut & paste job. >>>>>> >>>>>>Tom isn't the only corrupt reviewer, either. >>>>> >>>>> >>>>>I'm not going to debate that. Tom's hardware isn't the only place that is >>>>>doing these measurements. There are some well-known academics that are >>>>>interested in various benchmarks like streams, linpack, etc... >> >>You say, "I had some crafty benchmark data from that machine as well as the >>recent 2800+ AMD and I made the decision based on performance and nothing >>else...". The only way the 2800+ is going to be any slower is if the binary it >>ran had the 1.4x speedup problem. Email your source and have them test with one >>of my binaries. You could also take the dual 2800+ results and multiply them by >>1.214 (21.4% diff between 1.7 and 1.4). >> >>Also you say the + numbers are optimistic.. How so? My 1900+ at 1.8GHz (2200+) >>is on par with a P4-3GHz in Crafty. A 2600+ (Stock) could beat the P4-3.25GHz in >>the results list I have AND have room to spare. > > >I don't say that. AMD said that. And they are scaling their numbers back. >They >were using a raw estimate that every 66mhz increase in clock speed gave them >100mhz >of effective speed increase compared to the PIV. They discovered this failed at >the >beyond 2000 mhz clock frequencies and was "optimistic". Again, I assume they >know >what they are doing since they make the things... > > > >>By the way, AMD is currently working on Quad Opteron systems and there are test >>boards available. I don't know if you remember what I said in a previous message >>(not in this thread) but Opterons are going to have dual-channel DDR and memory >>banks and that dedicated bandwidth PER CPU. >>So if you have four CPU's and you're running 200MHz(400DDR) memory w/ dual >>channels thats 6.4gb/s per cpu. Total you'd have 25.6gb/s bandwidth. Oh, don't >>forget the CPU has it's own memory controller. > > >Right... and how are you going to read data out of memory where each bank has >100+ns >latency? I know how supercomputers do it. I don't think you are going to see >4-port memory >banks in a machine at that price point... > >Theoretical max is a nice concept. Attainable thruput is more interesting. At >present, Intel >seems to be leading that list by a significant margin. Whether they will in the >future or not >I don't know, as I try to not evaluate "vaporware". But for the moment, they >are on top in the >bandwidth war... as Linpack and other normal memory-intensive applications show >time after >time. > Take a look at this: http://www.amd.com/us-en/assets/content_type/DownloadableAssets/MPF_Hammer_Presentation.PDF > > >I hope they can deliver a quad opteron for a resonable price. They were talking >about quad >K7's two years ago and not a single instance has shown up yet. Intel talked >about the 8-way >boxes a while back and delivered a kludge there, using a "fusion" chipset to tie >two 4-way >clusters of processors together into a single 8-way box, but with terrible >memory performance. >They tried to offset that by only offering 2M L2 caches, but that drove the >price up and didn't >help memory-bound large applications at all... I hope the quad opterons don't >end up in >never-never land as the 8-way boxes did.. Here's a picture of a Quad opteron system if for some reason you think it's never going to happen... http://www.amdzone.com/articleimages/cpu/hammer/4popt.JPG There are many Dual Opterons out as well.. >If I recall, the 4=way dual 2.0ghz xeon is the fastest PC-class machine around >right now, >by a wide margin. And the heavier the load placed on it, the wider that gap >becomes...
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