Re: Mersenne: Need info about K6
I have a K6-2/300, and it is much slower than a Pentium. I actually use it for RC5 because it is so slow at LL testing, though I have a K6/233 doing factoring work. The K6 suffers because a) it can't do FXCH at the same time as another FP instruction (which Pentium's can), and also it can only do 1 FP instruction per 2 clocks at full load. I'd guess the performance is about the same as a P150 (I know coz that the K6/233 is about the same speed as a P100). It's a shame that the K6 can't compete with the Pentium here, because otherwise I find it to be fine for everything I use it for (games esp.) Michael. >On Thu, 25 Mar 1999, Bob Margulies wrote: >> I have just discovered that my wife is about to be presented with a new >> computer which contains a K6-2/333 processor, 64K L1, 512K L2, 64MB of >> SRAM. I would be willing to invest a few $$$ of my own in an upgrade to >> a Pentium if it made a substantial difference in running Prime95. My >> understanding is that the program has been optimized for the Pentium. >> The question is - how well does it run on the K6? >> >> Can someone please give me a comparison of the merits of the K6 vs. the >> Pentium? Also, please withhold comments on the domestic implications of >> the problem. Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
Re: Mersenne: Need info about K6
On Thu, 25 Mar 1999, Bob Margulies wrote: > I have just discovered that my wife is about to be presented with a new > computer which contains a K6-2/333 processor, 64K L1, 512K L2, 64MB of > SRAM. I would be willing to invest a few $$$ of my own in an upgrade to > a Pentium if it made a substantial difference in running Prime95. My > understanding is that the program has been optimized for the Pentium. > The question is - how well does it run on the K6? > > Can someone please give me a comparison of the merits of the K6 vs. the > Pentium? Also, please withhold comments on the domestic implications of > the problem. http://www2.tripnet.se/~nlg/mersenne/benchmk.htm Though it only has results for the K6, not for the K6-2, but the main speed advance for K6-2 was in the additional 3DNow! instructions, which aren't used for prime95, so it should still hold. -- Henrik Olsen, Dawn Solutions I/S URL=http://www.iaeste.dk/~henrik/ Get the rest there. Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
Re: Mersenne: Need info about K6
It's not actually optimized for a Pentium so much as the pentium is optimized for the kind of math that prime95 does. Prime95 uses the FPU (Floating Point Unit) extensively. The Pentium and Pentium 2 (and 3) can do a single FLOP (Flointing Point Operation) per clock cycle. It's a pipelined FPU. This means a 500MHz Pentium can do abou 500 MegaFLOPs. The K6 has a less advanced FPU and cannot perform one FLOP each clock cycle. It's significantly slower...perhaps it works arounf 50-75% of the speed of the Pentium FPU. However, the K6-2 has the 3DNow! instruction set (similar to P3's SSE) Which means that the 3DNow! Unit is basically a high speed but simpler FPU. The 3DNow! unit is like a RISC processor, it can do less sophicated things, but do them a lot faster. The unit can pump out 4 FLOPs per clock cycle. A 500MHz processor can theoretically do 2GigaFLOPs. However, I'm pretty sure Prime95 isn't coded for 3DNow! or SSE, and therefore this is irrelvent. It may be impossible to code for 3DNow! if the LL tests require instructions and code that isn't in the 3DNow! unit. I don't know enough math or programming to be able to answer that conclusively though. I don't have first hand knowledge, but can speculate that the K6-2 will perform at about 50-75% of what a Pentium can do clock for clock. But since the fastest socket-7 Pentium is 233MHz, and that K6-2 is 333, it should even out...well...actually the K6-2 will come out ahead. To get much faster performance you'll have to get at least a 300MHz P2 or Celeron, but that would require a motherboard upgrade, and that's an extra $100 on top of the CPU price... I'd stick with the free K6-2 and enjoy the extra CPU time that will go towards your account. :-) --Peter At 16:32 03/25/1999 -0800, you wrote: >I have just discovered that my wife is about to be presented with a new >computer which contains a K6-2/333 processor, 64K L1, 512K L2, 64MB of >SRAM. I would be willing to invest a few $$$ of my own in an upgrade to >a Pentium if it made a substantial difference in running Prime95. My >understanding is that the program has been optimized for the Pentium. >The question is - how well does it run on the K6? > >Can someone please give me a comparison of the merits of the K6 vs. the >Pentium? Also, please withhold comments on the domestic implications of >the problem. > >Thank you. > >Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm > Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
RE: Mersenne: Need info about K6
> From: Bob Margulies > Sent: Thursday, March 25, 1999 6:32 PM > Can someone please give me a comparison of the merits of the K6 vs. the > Pentium? Also, please withhold comments on the domestic implications of > the problem. It is my crude understanding that the floating point performance of the AMD chips are slower than on the Pentium core. Since the LL tests are FP intensive, one would expect chips of the same speed but different manufacture to differ in iteration speed. Now we just need someone to post that link to the Prime95 benchmark page which I always forget... Aaron Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
