Sek - that's interesting especially since I think all new IBM mainframes are CMOS based - rather than the older water cooled bipolar chips.

When I left data processing, IBM was planning on running almost any O/S under MVS - including Windows. I always though MVS was an incredibly good O/S - even though I never interacted with it directly.

I hooked up the kill-a-watt meter on the following machine

AMD 4800+ dual core overclocked by 10%
2 gig CAS 4 latency DDR2-800 RAM
4 SATA 7200rpm drives
a couple PCI cards like USB ports
graphics, network and audio are native to the ASUS m/b

It seems to run - under full CPU load and heavy drive access - at about 150 watts. So, I expect the other machines to come in under this number. I'll next try it on the other dual core machine

QX6700
Asus P5K Deluxe
Crucial Ballistix Tracer PC2-8500
D-Tek Fuzion water block
Swiftech MCP-655 pump
Dual 2x120mm radiators

BIOS settings:
CPU voltage: 1.45v
RAM voltage: 2.2v
FSB: 438MHz
multiplier: 8
FSB strap: 266MHz
RAM ratio: 4:5 547MHz (DDR2-1095)
Timings: 5-5-5-15

Intel Speed Step(EIST,C1E) is disabled, everything else was left at the stock/auto settings. With room temperature at 21c, my core temperatures read in the high 50's Celcius. Chipset temp is 30c.

Overclocking a quad core really puts a strain on the chipset and power mosfets, so when I got the board, I removed the heatpipe assembly and heatsinks, removed the stock thermal pads and applied Arctic Cooling MX1. I also have a couple fans blowing directly across the heatsinks so everything stays nice and cool. I've seen others report that the mosfets can reach over 100c with no active cooling. The new Asus P5K Premium supposedly addresses this issue by using higher quality components that create less heat.

The Intel P35 chipset really takes quad core overclocking to a whole new level. P965 was just "OK". Q6600 quad cores can now be bought for under $300, and if you can find a G0 "SLACR" stepping, 3.4-3.6GHz with air cooling seems to be the standard overclock. Highly recommended! 14,000 points/day on WCG is a nice bonus too!

Quad core power useage isn't as bad as it may look judging by my previous post. I have setup other barebones quad core machines with just a motherboard, RAM, CPU, 1 HDD and a few fans and they drew less than 200w each fully loaded running at 3.2GHz. Heat IS a problem though, with over 100w radiating from the cores, you need a top of the line air cooler or water cooling to keep it under control.

Stock voltage is 1.325, so I'm 10% over. Still considered mild in the OC community. Some guys run 1.5v or more for daily use. Plus 1.45 is my BIOS setting, actual voltage is 1.41 because core voltage always droops under load. It's been running like this for many months, no problem. But your right about the heat, I would not be able to run this overclock with any air cooler. Even with water cooling I can hit 75c on a warm day.

You are correct about the Mosfets, they regulate power to the CPU. Due to the low voltage, high amperage they see, they get incredibly hot. I can't speak for all motherboards, but on the Asus, there are several plastic pins with springs that hold the heatsinks to the board. The pins have fishhook-like barbs on the end that expand to grab hold of the MB. You can see the barbs from the backside of the board.

Here's a nice trick I found for getting the pins out effortlessly. Take a clicker style ball point pen, retract the point and then wiggle the tip onto the pin barbs. They will squeeze together and the pin will pop right out. After all the pins are out the heatsink will fall off.

MX1 is just a thermal grease. It's non-conductive and has the consistency of clay. So it won't short anything out or run all over the place and it's good at filling larger gaps. It's great for applications like this but for the CPU I still use Arctic Silver 5.

FSB strap is a BIOS setting(not all boards have it). It has to do with the timings of the FSB. Lower strap=tighter timings and better performance, but also means less FSB overclocking and less RAM ratio options. The options in the P5K BIOS are 200,266,333. The auto setting is 333 but mine runs stable at 266 so I left it there.

SLACR is a revision or stepping of the Q6600. Intel recently made some changes that fixed some mionor bugs and reduced the power consumption by 10w. The result should mean lower temps and higher overclocks. From what I've seen it's true. Here's what you are looking for http://img256.imageshack.us/img256/9929/dscf1769bs6.jpg Note the "SLACR" at the end of the product code. The older revisions will say "SL9UM". There are a few online retailers that will guarantee you the new revision, or you can walk into a store and choose it yourself. If you can't find one then don't worry, the older ones will OC 10-15% too easily.

I installed one of these in a friends rig, it runs at 3.2GHz 1.35v and core temperature is 50c with a high end air cooler. It could have went higher but the motherboard was not willing. I tested it in my own rig and got 3.6GHz easy.

I read the P5K premium reviews on newegg and I'm not sure what to think. 2 bad reviews isn't the end of the world though, I'm sure they sold hundreds more without issue. It's the same board as the Deluxe, just a few revisions in the power delivery area.

If you're just shooting for 3Ghz, then a cheaper board will suffice. But stick with a P35 chipset if possible. The Asus P5K and Gigabyte DS3R come to mind and there are many others.

I own a taxi company. Computers, overclocking and grid computing is just a hobby and passion of mine. If you need help with something, just hit me up directly. olympic.trans at sasktel.net