Dedicated Prime95 rig
 

Hey peoples,

Since AMD has released its new dual core 7550 and 7750 I've been thinking of creating a dedicated prime rig.

Would these be relatively efficient CPUs for prime, and is 1 gig of memory enough? Or should I get 2?

Additionally, if they are not reasonably priced here in Australia, would an AMD triple core be significantly more efficient than a 7750 or 7550?

& is there a preference to using linux or windows for prime, because for folding I know that linux is terribly faster for SMP folding than windows is.

Cheers :D

[quote=hj47;154511]Hey peoples,

Since AMD has released its new dual core 7550 and 7750 I've been thinking of creating a dedicated prime rig.

Would these be relatively efficient CPUs for prime, and is 1 gig of memory enough? Or should I get 2?

Additionally, if they are not reasonably priced here in Australia, would an AMD triple core be significantly more efficient than a 7750 or 7550?

& is there a preference to using linux or windows for prime, because for folding I know that linux is terribly faster for SMP folding than windows is.

Cheers :D[/quote]
if you are planning on doing ll tests dont get an AMD
an intel runs ~twice as fast on ll tests

Why is that?

[quote=hj47;154516]Why is that?[/quote]
i dont know why it is but it is a well known fact on this forum
when i upgraded from a 2.4 GHz Athlon 64 to a 2.4 Ghz Core 2 my speed at ll testing doubled per core yet for some other programs my Athlon 64 would have been faster per core

[QUOTE=henryzz;154521]i dont know why it is but it is a well known fact on this forum
when i upgraded from a 2.4 GHz Athlon 64 to a 2.4 Ghz Core 2 my speed at ll testing doubled per core yet for some other programs my Athlon 64 would have been faster per core[/QUOTE]

Quad-core Phenom doesn't work that bad after all...

Luigi

Yes, the athlon64 split SSE2 operations into two chunks done in sequence, whilst the core2 and phenom do the whole operation in a single chunk. So a 7550, which is basically half a Phenom, should have reasonable performance.

Though I suspect the price/performance will be significantly better if you use a 'Phenom II' (45nm quad-core) when they come out - the CPU costs about twice as much as the dual-core, but you don't have to have a second case, motherboard and memory.

[quote=henryzz;154515]if you are planning on doing ll tests dont get an AMD
an intel runs ~twice as fast on ll tests[/quote]
And while we are at it -- trial factoring to limits > 60 bits runs ~ twice as fast on AMD64.

Another wirdness I've found is that AMD64 is faster at 5120K and 6144K FFT than 4096K FFT when multithreading. At 5 threads 6144K FFT is almost as fast as 2048K! This makes me wonder if it is properly optimized for multi core multi CPU AMD CPUs. Here is selected benchmarks from an oldish machine with eight dual core 1 GHz Opterons:

[code]
Dual-Core AMD Opteron(tm) Processor 8218
CPU speed: 1000.31 MHz, 16 cores
...
Timing FFTs using 2 threads.
Best time for 3072K FFT length: 122.214 ms.
Best time for 3584K FFT length: 141.534 ms.
Best time for 4096K FFT length: 162.453 ms.
Best time for 5120K FFT length: 148.117 ms.
Best time for 6144K FFT length: 192.784 ms.
Best time for 7168K FFT length: 243.260 ms.
Best time for 8192K FFT length: 296.969 ms.
...
Timing FFTs using 3 threads.
Best time for 3072K FFT length: 113.277 ms.
Best time for 3584K FFT length: 147.447 ms.
Best time for 4096K FFT length: 145.264 ms.
Best time for 5120K FFT length: 105.272 ms.
Best time for 6144K FFT length: 125.552 ms.
Best time for 7168K FFT length: 154.236 ms.
Best time for 8192K FFT length: 184.660 ms.
...
Timing FFTs using 4 threads.
Best time for 3072K FFT length: 140.230 ms.
Best time for 3584K FFT length: 157.839 ms.
Best time for 4096K FFT length: 177.005 ms.
Best time for 5120K FFT length: 139.861 ms.
Best time for 6144K FFT length: 116.143 ms.
Best time for 7168K FFT length: 155.983 ms.
Best time for 8192K FFT length: 209.981 ms.
...
Timing FFTs using 5 threads.
Best time for 2048K FFT length: 87.582 ms.
Best time for 2560K FFT length: 122.746 ms.
Best time for 3072K FFT length: 141.399 ms.
Best time for 3584K FFT length: 160.135 ms.
Best time for 4096K FFT length: 179.035 ms.
Best time for 5120K FFT length: 114.527 ms.
Best time for 6144K FFT length: 90.497 ms.
Best time for 7168K FFT length: 113.099 ms.
Best time for 8192K FFT length: 139.041 ms.
...
[/code]5 threads seem to bee the sweet spot. From 6 to 16 threads there is very little improvement, and even degradation for some FFT sizes.

[quote=fivemack;154536]Yes, the athlon64 split SSE2 operations into two chunks done in sequence, whilst the core2 and phenom do the whole operation in a single chunk. So a 7550, which is basically half a Phenom, should have reasonable performance.

Though I suspect the price/performance will be significantly better if you use a 'Phenom II' (45nm quad-core) when they come out - the CPU costs about twice as much as the dual-core, but you don't have to have a second case, motherboard and memory.[/quote]
i didnt realise that the problem was solved in phenoms
thanks for a good explanation

I have another question;

Would it be more productive/efficient if I were to use a higher clocked single core with more available cache than a dual core with smaller cache per core?

I'm thinking of either using the Celeron 430 overclocked to 2.66ghz versus, say, a Celeron E1200 clocked at 2.0ghz? They both have 512k cache, the E1200 has it split in half for each core.

+++ Also, is there any advantage in running a 64 bit OS as opposed to a 32 bit, and is there any performance gain/loss to using the linux version of prime to prime95?

[QUOTE=hj47;155090]I'm thinking of either using the Celeron 430 overclocked to 2.66ghz versus, say, a Celeron E1200 clocked at 2.0ghz? They both have 512k cache, the E1200 has it split in half for each core.

+++ Also, is there any advantage in running a 64 bit OS as opposed to a 32 bit, and is there any performance gain/loss to using the linux version of prime to prime95?[/QUOTE]

I'd go for the dual core. Cache does make some difference, but generally the output of a single 2.66GHz will still be less than having 2x2GHz. People often ask the same about dual vs quads too - there the line is more blurred because of memory bandwidth bottlenecks, but I believe the quads are still more efficient (run 3x LL and 1x TF).

The 64bit OS is faster at trial factoring. But for LL and the rest there's no difference. I found no speed advantages of using linux. But if this is a dedicated p95 rig, you might not want to have a monitor etc linked up to it. With linux the advantage is you can make do without the monitor/keyboard etc and simply ssh into the box from another PC.

[QUOTE=db597;155097]But if this is a dedicated p95 rig, you might not want to have a monitor etc linked up to it. With linux the advantage is you can make do without the monitor/keyboard etc and simply ssh into the box from another PC.[/QUOTE]No need for a monitor with Windows either, simply download [url=http://www.uvnc.com/]UltraVNC[/url] (which is free), and you can easily access it visually through another PC on the network, or even over the internet if you set up port forwarding for it.

For overclocking in BIOS and such you would need a monitor though.

If you can stretch to it, an E8200 may perform significantly better than a Celeron due to a much larger cache (6 MB), and the overclocking headroom in the lower models is quite large. With a little patience and luck it seems [url=http://www.utheguru.com/overclocking-an-intel-e8200-core-2-duo-processor-2]you can add over another GHz to the stock clock[/url].

[quote=lavalamp;155325]No need for a monitor with Windows either, simply download [URL="http://www.uvnc.com/"]UltraVNC[/URL] (which is free), and you can easily access it visually through another PC on the network, or even over the internet if you set up port forwarding for it.
[/quote]

And no need for a graphics card either, but you cant use VNC, and must use the Windows-RemoteDesktop-Feature....

[QUOTE=Phantomas;155429]And no need for a graphics card either, but you cant use VNC, and must use the Windows-RemoteDesktop-Feature....[/QUOTE]Why can't VNC be used?

[QUOTE=lavalamp;155325]If you can stretch to it, an E8200 may perform significantly better than a Celeron due to a much larger cache (6 MB), and the overclocking headroom in the lower models is quite large. With a little patience and luck it seems [url=http://www.utheguru.com/overclocking-an-intel-e8200-core-2-duo-processor-2]you can add over another GHz to the stock clock[/url].[/QUOTE]The assesment by that person that the computer is Prime95 stable has to be taken with a grain of salt (well a rock of salt actually.) Going from 2,66 GHz to 3,92 GHz is quite a lot. Once you reach a "stable" speed, you should back up some 10 to 20 % with a resulting speed of 3,2GHz or 3,5 GHz if you are daring. Another thing to consider is that sometimes an increase in CPU speed can result in an effective increase in effective average iteration times when running real tests. You would not want to increase the current error rate and worse have your computer running for worthless resultzs...

Jacob

[quote=lavalamp;155437]Why can't VNC be used?[/quote]

It seems, that vnc needs/uses the existing framebuffer of a graphicscard. No card, no buffer. Windows DesktopRemote seems to work like a graphic-card simulation.

[QUOTE=hj47;155090]+++ Also, is there any advantage in running a 64 bit OS as opposed to a 32 bit?[/QUOTE]

Yes. The next version of prime95 will have a few tweaks using the extra registers. Not a big difference, but every little bit helps.

[QUOTE=Phantomas;155440]It seems, that vnc needs/uses the existing framebuffer of a graphicscard. No card, no buffer. Windows DesktopRemote seems to work like a graphic-card simulation.[/QUOTE]Yes, I concur with that. With VNC you always get the remote system's screen resolution presented on your monitoring system. With WRD you get the native resolution of your monitoring system.

Just to be clear what I mean. I have my monitoring system with a native resolution of 1400x1050 and the remote system running P95 is 1280x720.

With VNC I get a small window of 1280x720 presented to me that is an exact duplicate of what the remote system is displaying (they work simultaneously and both display everything that is happening, including mouse movements).

With WRD I get a full screen window 1400x1050 to work with and the remote system is logged out displaying the log in screen. The mouse movements are not echoed to the remote system. Indeed the OS starts an entirely new session for the monitoring system on the remote system with two copies of "winlogin.exe" running in the task list.

The only catch is that you need Windows Professional (or higher) on the remote system to run WRD. It needs the terminal services driver running also.

[eidt]
One thing to be careful about if security is important. WRD is an encrypted session and is better suited to Internet monitoring IMO. VNC (at least the version I have) is not an encrypted session.

[quote=retina;155567]Yes, I concur with that. With VNC you always get the remote system's screen resolution presented on your monitoring system. With WRD you get the native resolution of your monitoring system.

Just to be clear what I mean. I have my monitoring system with a native resolution of 1400x1050 and the remote system running P95 is 1280x720.

With VNC I get a small window of 1280x720 presented to me that is an exact duplicate of what the remote system is displaying (they work simultaneously and both display everything that is happening, including mouse movements).

With WRD I get a full screen window 1400x1050 to work with and the remote system is logged out displaying the log in screen. The mouse movements are not echoed to the remote system. Indeed the OS starts an entirely new session for the monitoring system on the remote system with two copies of "winlogin.exe" running in the task list.

The only catch is that you need Windows Professional (or higher) on the remote system to run WRD. It needs the terminal services driver running also.[/quote]
On Linux you can set the VNC server to serve up exactly whatever resolution you want. For example, on a friend of mine's machines which he manages via VNC while away, he starts the VNC server with a shell script that runs the following command:

[I]vncserver -geometry 1024x768 -depth 24[/I]

Also, like WRD, VNC on Linux starts an entirely separate session of the username it's run under. (Note: some implementations of VNC, such as the "Remote Desktop" feature built into Ubuntu and possibly some other GNOME-based distros, behave more like the Windows version, i.e. taking direct control of the console session. My friend is using Ubuntu, but we installed TightVNC, which uses the separate-session method, on his machines and are using that instead of the built-in VNC server.)

The VNC session can be started with whatever resolution you'd like--though admittedly, unlike WRD, it does not dynamically resize the resolution based on a setting in the connecting client. VNC's resolution setting is set on the server, though under Linux it does not have to be the same as the console session's resolution due to it starting a whole new session.

[quote][eidt]
One thing to be careful about if security is important. WRD is an encrypted session and is better suited to Internet monitoring IMO. VNC (at least the version I have) is not an encrypted session.[/quote]
Hmm...I didn't know WRD was encrypted. I've always heard that it was unencrypted, like VNC.

The free versions of VNC are all unencrypted; some for-pay versions of some distros of VNC have encryption options. However, the easiest way to encrypt a VNC session--for free--is to tunnel it through an SSH connection. This can be done with a command like this:

[I]ssh user@remote-host -L 1234:127.0.0.1:5900[/I]

The above command will start a tunnel to port 5900 (i.e. the default VNC port) on the remote machine, and pipe it through to 1234 on the local machine. Then, on the local machine you can set your VNC client to talk to 127.0.0.1 port 1234, and it will connect to the remote server's VNC desktop, through the encrypted SSH tunnel.

For secure VNC over t'internet, I just use [url=https://secure.logmein.com/products/hamachi/vpn.asp?lang=en]Hamachi[/url], it's a free VPN.