Windows XP 64-bit trial available
 

For those of you with Opteron of Athlon 64 processors, you may be interested in this: [url]http://www.microsoft.com/windowsxp/64bit/downloads/upgrade.asp[/url]

As a side request, if any of you guys decide to try this out could you please test Prime 95 and run the benchmark and post to this forum.

Thanks

Check out this too:
[url]http://www.microsoft.com/windowsserver2003/64bit/extended/trial/default.mspx[/url]

I didn't test it on Win64. But the difference between a 32bit app on 32bit OS and the same app on 64bit OS will be very small if at all noticeable as long as it doesn't depend that much on drivers (e.g. like 3D games do).

So here you go first Windows 2003 Server 32 Bit, second Windows XP Prof for AMD 64, notice the P95 cache settings.


AMD Athlon(tm) 64 Processor 3200+
CPU speed: 2014.21 MHz
CPU features: RDTSC, CMOV, PREFETCH, MMX, SSE, SSE2
L1 cache size: 64 KB
L2 cache size: 128 KB
L1 cache line size: 64 bytes
L2 cache line size: 64 bytes
L1 TLBS: 32
L2 TLBS: 512
Prime95 version 23.8, RdtscTiming=1
Best time for 384K FFT length: 22.886 ms.
Best time for 448K FFT length: 27.326 ms.
Best time for 512K FFT length: 30.916 ms.
Best time for 640K FFT length: 38.578 ms.
Best time for 768K FFT length: 47.187 ms.
Best time for 896K FFT length: 56.095 ms.
Best time for 1024K FFT length: 63.441 ms.
Best time for 1280K FFT length: 82.824 ms.
Best time for 1536K FFT length: 99.374 ms.
Best time for 1792K FFT length: 122.561 ms.
Best time for 2048K FFT length: 138.590 ms.


AMD Athlon(tm) 64 Processor 3200+
CPU speed: 2014.01 MHz
CPU features: RDTSC, CMOV, PREFETCH, MMX, SSE, SSE2
L1 cache size: 64 KB
L2 cache size: 128 KB
L1 cache line size: 64 bytes
L2 cache line size: 64 bytes
L1 TLBS: 32
L2 TLBS: 512
Prime95 version 23.8, RdtscTiming=1
Best time for 384K FFT length: 23.033 ms.
Best time for 448K FFT length: 27.466 ms.
Best time for 512K FFT length: 30.957 ms.
Best time for 640K FFT length: 38.585 ms.
Best time for 768K FFT length: 47.346 ms.
Best time for 896K FFT length: 56.321 ms.
Best time for 1024K FFT length: 63.226 ms.
Best time for 1280K FFT length: 82.534 ms.
Best time for 1536K FFT length: 99.062 ms.
Best time for 1792K FFT length: 122.167 ms.
Best time for 2048K FFT length: 138.233 ms.

I found that from usenet
 

---klip--klip---
According to a post in microsoft.private.windowsserver_64bit by a compiler
author, XP64 does not save the x87/MMX registers during context switches.
Maybe this is to offset the cost of saving more GPRs and XMMs in AMD64 code?

---klip--klip---

This might affect to prime95 ?

Yours,

Nuutti

[QUOTE=nuutti]---klip--klip---
According to a post in microsoft.private.windowsserver_64bit by a compiler
author, XP64 does not save the x87/MMX registers during context switches.
Maybe this is to offset the cost of saving more GPRs and XMMs in AMD64 code?

---klip--klip---

This might affect to prime95 ?[/QUOTE]

That's only valid for 64bit software. 32bit software, which would run behind a "Windows on Windows" translation layer (not translating code, but function calls to the system) could still use the x87 regs without a problem. But even in this case Prime95 would use SSE2 (with standard configuration) because it's there.