What makes a good RC5-72 cruncher?

[Geier]

I'm looking at building another cruncher or two around the end of the summer and I am wondering what makes for a good RC5-72 machine? I know the Macs kick butt, but I am looking for something more economical (and not a Mac). I may even build basket crunchers (or blades), so I need to know how to get bang for my buck when I start getting hardware together.

This is what I have running RC5-72 now:
1 - Athlon64 3000+ @2Ghz, Asus K8V Deluxe, 512MB (2x256) PC3200 DDR -- 8,000,000+ keys/sec
1 - Dell Optiplex GX260, P4 2.4Ghz, 256MB PC2100(?) DDR - 4,000,000+ keys/sec
100 - Dell Optiplex GX150, PIII 1Ghz, 512MB (2x256) PC133 SDRAM - 2,000,000+ keys/sec

I can't afford any more Athlon 64's for a while, but if I could I would probably go with the FX-51(or is that the FX-53?) that can be used with unregistered Ram.

So here are a few questions:
- Does RC5-72 run better on Linux or Windows? I think it's Windows, but which version of Windows?
- Which does RC5-72 need more: FSB, CPU speed, memory speed, or other?
- Does RC5-72 benefit from higher L2 (or L3) cache?
- Does RC5-72 need a lot of Ram? What type of ram (buffered, registered, ecc, etc...)?
- Does RC5-72 benefit from multiple cpu systems, or does it lose something in the process? Is it better to run RC5-72 on 4 single-cpu systems, 2 dual-cpu systems, 1 dual-cpu system with hyperthreading, or 1 quad-cpu system?
- Which processors will give me the best bang for my buck on RC5-72? Keep in mind that I am considering Total Cost of Ownership, which includes the cost of electricity. I would rather run one Athlon 2500+ than 3-733's.

[Geier]

It would be nice if it would also be a good general purpose cruncher in case I wanted to participate in another project during a gauntlet.

[Bok]

I'm not sure about the speed, but for price alone you can't really go wrong with an XP2500 + nforce2 board and 256Mb PC2700.

I got 2 A7N8X-VM's refurbished from newegg this week for $45 each. They have on-board graphics.

I actually put 2 XP2800's in yesterday, a 256Mb stick of ram and installed Gentoo Linux on each to add to the home farm..

I don't think windows/linux makes any difference on dnet, I would go for linux personally for cost and ease of use.

Bok :D

[TheOtherPhil]

dnet will run entirely from the cache of the CPU therefore fsb/ram speed isn't an issue. An SDRAM system will cunch exactly the same as the latest DDR systems as long as the CPU and core speed remains the same. The core speed of the CPU is what really counts....the higher the better. Also bear in mind that there is no difference in performance between processors based on the same core - eg. a Duron performs exactly the same as an XP, a PIII performs the same as the Celeron and a P4 performs the same as the P4 Celeron (assuming equal clock speed).

Stay away from the P4 based processors. Although macs are wicked fast, the best bang for the buck is a Duron based system, 128MB RAM and an all in one mobo. There is very little difference when running Linux/ Windows.

[DesertFolk]

I agree TheOtherPhil. Last week I got a Biostar M7NCG 400 motherboard ($61), a 1.8GHz Duron ($46), 256MB of PC2700 Ram, and a couple of cpu fans. I bought 2 fans for $19.50 instead of 1 for $15.99. I can upgrade to an Athlon XP up to 3400+ with that motherboard later if I want to, and it supports dual channel memory if I want to run something other than RC5-72 on it.

Links:
BIOSTAR "M7NCG 400" nForce2 IGP Motherboard for AMD Socket A CPU (http://www.newegg.com/app/viewProductDesc.asp?description=13-138-234&depa=0)
AMD Duron 1.8GHz Socket A Processor (http://www.newegg.com/app/viewProductDesc.asp?description=19-104-160&depa=0)
Tr2tt (Designed by Thermaltake) Tr2M1 CPU Cooler for Socket A/ 370, Model "A4001D" (http://www.newegg.com/app/viewProductDesc.asp?description=35-106-602&depa=0)

I am very happy with it so far. It is running 6,750,000 keys/sec straight out of the box (no oc). I don't have it in a case; it's just sitting on a table. The lights on the cpu fan act as a nightlight. ;)

It is running Win2k with SP4, but I have disabled most of the superfluous services. No antivirus or any other programs that are unnecessary on a cruncher, but I did run Windows update to get all the security patches.