Search found 87 matches

by shatteredsilicon
Wed Aug 26, 2009 11:36 pm
Forum: FAH Hardware
Topic: CPU Architecture and FAH
Replies: 58
Views: 37765

Re: CPU Architecture and FAH

divery4eyes wrote:sad to say, but I do not foresee AMD being with us much longer :-(
We can but hope. Then maybe we can finally knock x86 on the head once and for all.
by shatteredsilicon
Sat Aug 08, 2009 7:47 am
Forum: Discussions of General-FAH topics
Topic: On XBOX 360?
Replies: 3
Views: 625

Re: On XBOX 360?

It wouldn't be worthwhile. PowerPC performance is appalling, and there are no compilers available that can vectorize code on VMX128 (Xenon FPU is a bit different to the standard PPC970 - Xenon is missing about 20 Altivec instructions, but has additional 128 registers).
by shatteredsilicon
Fri Jul 10, 2009 7:01 am
Forum: FAH Hardware
Topic: CPU Architecture and FAH
Replies: 58
Views: 37765

Re: CPU Architecture and FAH

So, if I'm following this correctly, you are asking what CPU will be sufficient to saturate whatever number of GPUs you are planning to have. If that's the case, then I can confirm that my own experience indicates that it takes approximately 15-20% (depending on the WU) of a 2.6GHz+ Core2/Phenom cla...
by shatteredsilicon
Thu Jul 09, 2009 6:37 pm
Forum: FAH Hardware
Topic: CPU Architecture and FAH
Replies: 58
Views: 37765

Re: CPU Architecture and FAH

You'll need to define your goals more precisely. Are you looking for maximum PPD/$ in terms of initial investment? Or PPD/W (ongoing electricity costs)? There are threads elsewhere on this forum for PPD/$ and PPD/W figures for most commonly available hardware. (Somebody also threatened to start PPD/...
by shatteredsilicon
Wed Jul 01, 2009 11:16 pm
Forum: Scientific discussions (Non-FAH)
Topic: AMD to support Nvidia's CUDA technology?
Replies: 12
Views: 5350

Re: AMD to support Nvidia's CUDA technology?

The problem is that nVidia and ATI architectures are fundamentally different. nVidia is MIMD, ATI is SIMD. In a nutshell: MIMD: Pros: Easier to write a decently optimizing compiler. Less dependent on programmer competence. Cons: Requires more silicon to implement thus more expensive, worse performan...
by shatteredsilicon
Wed Jun 24, 2009 11:46 pm
Forum: Discussions of General-FAH topics
Topic: Infinite CPU speed = 'instant cure' for some folding apps?
Replies: 7
Views: 2886

Re: Infinite CPU speed = 'instant cure' for some folding apps?

The problem is that the bottleneck of the problem shifts away from the simulation and toward understanding. In other words, the scientists become the bottleneck because data takes time to fully understand. And once that understanding is achieved, there is still the issue of synthesizing chemical com...
by shatteredsilicon
Sun Jun 21, 2009 10:30 am
Forum: FAH Hardware
Topic: CPU Architecture and FAH
Replies: 58
Views: 37765

Re: CPU Architecture and FAH

I rather suspect the best PPD/$ and PPD/W figure would likely go to one of these:
http://www.supermicro.com/products/moth ... .cfm?typ=H (£115+VAT in UK)
coupled with something like a good old 9800GX2. This mobo has a PCIe x8 slot, so it would probably work reasonably well.
by shatteredsilicon
Sat Jun 20, 2009 2:29 pm
Forum: FAH Hardware
Topic: CPU Architecture and FAH
Replies: 58
Views: 37765

Re: CPU Architecture and FAH

Another thing worth pointing out that SSE2 capable units will still run on SSE1-only hardware, they'll just run slower. The core auto-detects what can be used and uses whatever is available. Any floating point features that are missing from the hardware being used get executed using the 387 FPU call...
by shatteredsilicon
Sat Jun 20, 2009 12:12 am
Forum: FAH Hardware
Topic: CPU Architecture and FAH
Replies: 58
Views: 37765

Re: CPU Architecture and FAH

The two are unrelated. It doesn't matter whether double or single precision numbers are used - that part is WU/core specific. There is no issue of efficiency here. Doubles are only used where they are needed - it is not about efficiency, it's about necessity. The other point about utilization is deb...
by shatteredsilicon
Fri Jun 19, 2009 9:30 pm
Forum: FAH Hardware
Topic: CPU Architecture and FAH
Replies: 58
Views: 37765

Re: CPU Architecture and FAH

I'm not sure I follow what you're saying, cheechi. SMP and SSE/SSE2 are totally orthogonal in the logical sense.
by shatteredsilicon
Thu Jun 18, 2009 7:51 pm
Forum: FAH Hardware
Topic: CPU Architecture and FAH
Replies: 58
Views: 37765

Re: CPU Architecture and FAH

So would this be more efficient use of a dual core CPU than a wu using SSE? Or compared to a quad core running the SSE2 wu? Typically, if your algorithm is well adjusted to the CPU, SSE1 will give you approximately 4x speed-up on floats. SSE2 will give you a 2x speed-up on doubles. Multiple cores s...
by shatteredsilicon
Sun Jun 14, 2009 11:41 pm
Forum: FAH Hardware
Topic: CPU Architecture and FAH
Replies: 58
Views: 37765

Re: CPU Architecture and FAH

- GroSMP is a bit different : it doesn't stresses CPU as hard as regular Gromacs because processing power is limited by data transfers between CPU cores This affects quad Core2s particularly badly, among other things that the two sets of two cores are completely separate without shared chaches betw...
by shatteredsilicon
Mon Jun 08, 2009 9:57 pm
Forum: Discussions of General-FAH topics
Topic: Selective Folding (branched from Nvidia issues forum)
Replies: 32
Views: 6158

Re: Selective Folding (branched from Nvidia issues forum)

For me, optimum is 75C. I can do 75c massively shader OC'd and mem and core stock Wow! All I can say is wow . I cannot even begin to come up with words to respond with to that. So you are expressing vehement concern about temperatures and yet you are admitting to "massively" (your words, ...
by shatteredsilicon
Sun Jun 07, 2009 12:21 pm
Forum: Discussions of General-FAH topics
Topic: Selective Folding (branched from Nvidia issues forum)
Replies: 32
Views: 6158

Re: Selective Folding (branched from Nvidia issues forum)

Pandegroup appears to address the issue of dumping by adding tracking based on ip and re-issuing the same workunit. On mine when ive had failed workunits its been a pain to get new workunits as it seems that after 3 tries your ip gets blacklisted for 5 mins or so. Sounds like you didn't clean up pr...
by shatteredsilicon
Mon Jan 12, 2009 1:07 pm
Forum: Scientific discussions (Non-FAH)
Topic: PS3 Uses 5x more Electricity than Fridge [Not true]
Replies: 66
Views: 28032

Re: PS3 Uses 5x more Electricity than Fridge

For example, which vehicle is more environmentally friendly to manufacture? A tiny little Prius or a giant Hummer? Sounds like an easy question doesn't it. Guess what, making a Prius contributes more carbon to the atmosphere than making a Hummer, largely due to the environmental cost of the 30 poun...