Mav's P4 temp reading is probably right.
Mine is running from 77-80C according to my BIOS using the stock cooling fan and Arctic Silver 5, and that's not even under 'real' load.. given that I'm at the BIOS screen and Windows XP isn't running yet.
Right now my system is:
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RAIDMAX Smilodon case; 80mm back exhaust fan, 2 80mm side fans one being exhaust and 1 being intake for cycling air over my GPU, 1 120mm front intake fan pulling air over the HDD.
RAIDMAX 550W PSU. Came with the case.
GIGABYTE GA-8N-SLI nForce4 Intel Edition rev 1.1 motherboard. Flashed the BIOS today to version F6 from F5, to see if it helped out with CPU microcode and stepping.
Pentium 4 Prescott 3.0ghz CPU, HT turned on. As I mentioned, mine reports to running as hot as 80C in the BIOS.
Stock heatsink that came with the P4. I know, shame on me for using that piece of trash.
2x1gig Corsair DDR2 667 RAM.
EVGA GeForce 256mb 7950GT PCIe x16 video card, core clock 550 mhz, 700mhz memory clock (350 mhz effective per channel, or course). It runs at about 56C according to my nVidia Control Panel with nTune installed when I'm not gaming. Gets to about 60-61C when playing FEAR or Far Cry or World of Warcraft. Kinda scares me a bit to see it get that warm, haha.
HDD is some old Seagate IDE 120gig 7200 rpm drive. I hate it, and want to replace with a nice 250+ gig SATA with a nice cache, but I'm a cheap bastard and won't spend the money yet.
The other parts aren't really worth mentioning, naturally.
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I know I can save myself a lot of trouble if I just get like a Zalman 9700 heatsink or something and a better case with more fans made out of aluminum instead of steel. I attribute a lot of the slowdown I get from playing newer games like STALKER to the heat my machine is under, either due to insufficient air flow and my video card running too high, or because my P4 is so hot. Not to mention my crap HDD with only like a 1mb cache and it being IDE.
I've got no problems running FEAR and Far Cry on full detail at 1024x786x32@60hz and getting nice, smooth frame rates, but when I fire up STALKER and try to run it with even half detail at the same resolution it plays like garbage. I've tried looking at my RAM timings, overclocking my 7950GT, and making a hardware profile at boot to stop all nonessential services and processes, but to no avail.
I guess investing in a DirectX10 machine would be more wise than buying a whole new case and whatnot. Perhaps if I'm going to go that far I might as well save up and buy the rest of the parts to make a new PC and just sell this one for whatever I can get to some kid that wants to play WoW.
At any rate, this whole entire rant and wall of text was based around Mav's P4 running hot.. and so is mine, haha.