I’d like to share some overclocking experiences of mine with you. It all started out when I just got bored of my PII-450 running quietly along at 504, as my P2B-S doesn’t allow higher clockspeeds. I just wanted to go do real overclocking again. So I bought myself 2 week 35 C366’s. These baby’s ran just great at 566 MHz @ 2.0v, which put a big smile on my face, considering I paid the equivalent of $70 for them here in The Netherlands.
But of course, this wasn’t enough. Like every hooked overclocker, I wanted more – 615 MHz, as that was the limit of my board. So reading a few reviews here and there I decided to get the highest performing Global Win FDP 32. But, it was a no go. Even the FDP 32 couldn’t get them to 615.
Next option was a peltier, so I got the well known Tom Leufkens peltier set. After a few minor modifications to my FDP 32, I booted up. Everything went fine…. Booted up… Lock…. S^$T. Other CPU… Booted up…locked in CPU Mark99, which was a sign for me that the second CPU was more stable. Of course I tried all voltages… But heat was my main problem, because the FDP 32 started to cook. Even strapping 2 80mm case fans on it didn’t help.
By that time I had ordered a couple of 72 watt peltiers to see if that would help (Tom’s are rated at 52w, this is all at 14.4v). I strapped it to the FDP 32 case fan setup again but this didn’t help a bit. The FDP 32 got so hot I couldn’t touch it anymore. I was starting to get very disappointed. Would 615 be possible at all?
By this time, I had just received the Alpha 6065. With little hope (as “the Alpha killer” wins all the tests), I strapped the 72 watt peltier to the Alpha. I started the PC at 615 MHz, 2.0v. I couldn’t believe it – I had a stable desktop and could run CPU Mark99, as many times as I wanted! Ok, Quake3 next – played it for an hour without a crash!
I couldn’t believe it, was the “Alpha killer” beaten by the Alpha?? The answer was a very simple “Yes”. The Alpha got warm, but I could still touch it. It was not nearly as warm as the FDP 32 with 2 case fans blowing at it.
This led me to the following conclusion:
The FDP 32 is the best performer at relatively low loads of power; but attach a peltier and it will have to dissipate between 85 and 100 watt of heat depending on the peltier you are using. The FDP 32 just can’t cope. The sink gets so hot that, in my opinion, it’s effectiveness just plunges.
The Alpha however seems to have a much better overall performance. The FDP 32 might whip its ass a low power load, but it’s just worshipping the Alpha when you strap a peltier on there.
The next thing surprised me a bit too. Having found what I was looking for, I removed the 72 watt peltier (Melcor by the way) and strapped the Tom Leufkens unit on again. My stability went as fast as it came. I could still run CPU Mark99, but only 3 times before my PC crashed. Quake 3 crashed about 2 minutes into play. I swapped again for the 72 watter and everything was fine again.
This really surprised me; at 12 volts Tom’s peltier should be able to transport 43 watts, which is more than what my C366 puts out at 615 MHz. It’s hard to draw a conclusion from this as I don’t have any way of testing what is going on and I didn’t feel like going into calculations. I’ll leave the conclusion of this to you. But it is easily said that it has to do with core temperature.
I must say that I didn’t get the 100% stability mark with my Alpha and 72 watt peltier. Yes, it ran Stability tester all night, but my ultimate test is one I haven’t seen used before – Adobe Photoshop’s smudge tool with a high res picture. Just create a 25 MB file, better, enlarge a photo to this size and start smudging. I guarantee you, if the CPU survives that, it’s 100% stable.
But my best 366 still managed to crash when the smudge tool was used. But remember this is all at 2.0v. I didn’t gain anything with higher voltages. I think this was a heat problem.
This weekend I will be trying to solve this with a big copper hot plate sticking out on top so I can sandwich 2 extra smaller heatsinks. If this doesn’t get it stable, no air cooling will! Or maybe the HP Polarlogic – I’m expecting next week.
My final word would be, don’t combine the Global Win FDP 32 with a peltier – just get the Alpha and you’ll be a happy camper.
COMMENT: I think Elmer’s 366s need a low temperature to hit his objective. Even though Tom’s 43 watt peltier might seem adequate, if the C366 requires something like 0-5 C, Tom’s unit won’t get you there. For each CPU, certain speeds are only attainable at or below a given temp – finding it and getting there is the challenge!