Author: Robert Hyatt
Date: 15:05:52 01/20/01
Go up one level in this thread
On January 20, 2001 at 17:24:16, Vincent Diepeveen wrote: >On January 20, 2001 at 14:13:03, Robert Hyatt wrote: > >>On January 19, 2001 at 18:19:51, Vincent Diepeveen wrote: >> >>>On January 19, 2001 at 09:13:57, David Wilke wrote: >>> >>>>It has been stated by Robert many times that Crafty is blazing fast on an Alpha >>>>processor. >>>> >>>>If this is the case, why wouldn't he use Alphas to run Crafty on the chess >>>>servers instead of the big gun Xeons? >>>> >>>>What would be the actual cost of a Quad processor Alpha machine? >>>> >>>>And how much faster would Crafty be on that hardware? >>> >>>Recently (november) a dual mainboard came out for alpha at 866Mhz. >>>Around 2500us$ ONLY for the motherboard. >>>And correct me if i'm wrong, but it doesn't give a hardware 2.0 speedup. >>> >>>A cool MSI dual 694d motherboard allows processors (PIII fcpga) at >>>like 1Ghz or above. It's $200 at most. >>> >>>So it's realistic to say alpha's are about 10 times pricier. >>> >>>A 16 processor alpha recently sold for 8.5 million dollar. >>>I forgot the speed of the alpha's on that system. somewhere between 450 >>>and 600 Mhz i think. >>> >>>Also it's not realistic to assume that we'll see alpha's in the stores >>>breaking the 1 Ghz barrier in dual motherboards. >>> >>>If a dual alpha 21264 would be not too expensive i might just for >>>fun buy one, but just $2500 for the motherboard to start with is >>>not exactly big fun. >>> >>>That's out of my price range for sure. The 866Mhz speed i don't >>>even complain about as it's not realistic to expect any production >>>64 bits machine with so many registers like the alpha has to >>>get over 1 Ghz. >> >>Digital has had alphas running over 1ghz for quite a while. However, their >>lowly 600mhz processor blows off anything Intel can offer... floating point, >>integer, memory bandwidth, you-name-it... > >a 21164 alpha had 8kb L1 cache. You forget 96KB of L2, and probably 1M of L3... >though my program is using 'int' everywhere, >it's using a lot of code for its evaluation. Especially >a lot of tables to look up scores. > >a 633Mhz 21164 performed like a PII at 380Mhz for DIEP a few years >ago. > >But for 2388$ just for a dual mainboard that perhaps in hardware >already doesn't get a 2.0 speedup over a single cpu, it's hard >to imagine how much faster an 21264 is for my DIEP. > >Those integer speed tests never were a good measure for my software. >I'm also talking about some security programs that encrypted a few >texts. They flew on the alpha because of its 64 bits wide registers, >but if i compiled the 32 bits version and compared that with PII, >then the PII was even faster on that integer multiplying arrays >thing, even though no PII instructions were used to eliminate branches. > >No program i compiled myself ever was faster on alpha when a fair >comparision was done. I gave two test runs, one on a Xeon 700 with 1MB L2, compared to a 21264 at 600. Running Crafty over a long test suite. The alpha was 2x faster, clearly. > >I don't doubt that the 21264 is faster as a PII, but >let's do a fair compare. I did a compare against a PIII with a bigger L2 cache than anything you can get in a non-xeon version... That is the best of the PIII processors, and the alpha beats it 2x clock for clock... > >Fastest factory buyable processor which is from the same >generation (so a P4 1.5Ghz is not a fair compare) >as the 21264 is a K7 at 1.2Ghz (so i'm not talking >about overclocking it to 1.6Ghz as some people managed >but about the speed at which they get sold). > >What is the fastest single cpu alpha 21264 as it leaves factory, >866Mhz? I am not sure... The speed of crafty is well over 1M on that machine, which no pentium can come within 50% of. > >On paper seen the alpha can at most be 25% faster as a K7 as its >only advantage is that it can do 4 instructions a clock versus K7 >3, but it has of course a WAY bigger branch misprediction penalty. > >So i see no way to outgun a K7 at 1.2Ghz by a big margin. > >Now let's go on to the dual. Fastest clock you can get a dual >now is a slot1 PIII800 RDRAM dual overclock it with a peltier elements to >1.1Ghz. > >Versus dual alpha 21264 with the only 2 months ago released >motherboard 2000+ at 866Mhz. > >First question: how much hardware penalty do 2 alpha processors >get for cooperating together? No more than for 2 pentiums. Should be exactly the same except that the alpha has a _much_ better bus... > >I remember rumours that they don't give a 2.0 hardware speedup because of >some communication speed issue. Is that still true or only a rumour? > >In my eyes no way this system however is going to kick butt of >the P3-cumine by a big margin. > >And we need to very clearly realize that despite the big money >alpha costs that this 866Mhz dual motherboard only was released >end NOVEMBER 2000. Not sure which MB you are looking at. Compaq has had multi-alphas for several years... > >If 32 to 64 bits speedup is no big deal for a program then this >dual alpha is already slower as the fastest >dual K7 or PIII when you can buy it in the stores! I'd take that dual alpha any day, myself... based on experience running on them... > > >> >> >>> >>>It's more realistic to say that it might take 2 years before we >>>see that. AMDs will be running probably dual then at 2 Ghz for >>>less as 1/10 of alpha prices.
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