Alpha PFH6035MFC/Peltier vs Mushkin Tundra: The Good, the Bad and the Ugly.
Every once in a while you get to compare the best and worst of things – The Alpha PFH6035MFC is without a doubt the best example of a well engineered Socket 5/7/370 heatsink. Coupled with a peltier, it has the potential to be the best PPGA cooling solution any overclocker can find.
I test heatsinks using a 40 watt peltier to simulate a C300a at 2.3 volts running at 504. This is a lot of heat for any heatsink to dissipate – it is a torture test. For a heatsink to fail this test is to brand it as unsuited for overclocking.
In my testing, I found that the Alpha PFH6035MFC can dissipate 80 watts of heat without blinking an eye. I am amazed. In this test I used one 40 watt peltier on the Alpha and mounted it onto my 40 watt peltier test rig. This is 80 watts of heat to dissipate.
The Alpha maintained a cold side temp of -3.3 degrees F. I then over-volted the Sunon fan (ran it at 15 volts) and got a cold side temp of -7.8 degrees F. Anyone who knows about peltiers will tell you that the toughest thing to do with peltiers is to build a cascade – putting 2 together so that you get a cold side temp lower than what can be achieved by a single peltier. For the Alpha to achieve this is remarkable.
This is only a preliminary report on the Alpha – PCNUT is lending me a PPGA C366 to try with the Alpha/Peltier combo to see if we can hit 550. I hope to have some results for you soon.
“Mikewarrior” (firstname.lastname@example.org) sent us an email about his Alpha/Peltier experience as well:
“I ordered an Alpha heatsink and installed it on my 300a PPGA/BM6. It ran great. Then I got the idea to use a peltier from you guys (from the Mushkin Peltier Review [see below]). After modifying the temp diode underneath the CPU, these are the following results I have received at 540:
My setup includes, a 3/32 Aluminum Cold Plate, a 1/16 Copper Hot plate, and a 40mmx40mm x 4.7mm peltier cooler(65 degree variance model).
540 @ 1.8 Volts
CPU Temp: Hardware Monitor IDLE Throttle: 14 degrees C (57F)
CPU Temp: Quake 3 Test: 24 degrees C (75F)
CPU Temp: Startup TEMP: 22 degrees C (72F)
So, pairing an Alpha heatsink with a Peltier worked extremely well for me. I’m curious to find out how you guys did with one.”
Funny you should ask…Skip had the following results:
“Mounted a Peltier on the Alpha Socket 5/7/370. All temps from Temp header under CPU on a BM6. Readings taken after 10 minutes of running Prime 95:
Celeron 300 PPGA clocked at 504 2.1 Volts. Room Temp 80 F:
Alpha alone: 95 F
Alpha with 40 mm Peltier: 75 F
Alpha with 40 mm Peltier and 1/8″ Cold Plate: 60 F
When sitting idle at the Windows desktop, the Alpha with Cold Plate after about 20 minutes the temp drops to 42 F!!!!!!!!!!!!!! Now, this is with an open case.
Condensation IS a problem. Oh yeah, with the Alpha and Cold Plate, this chip will run 527 @ 2.0 Volts! Previously required 2.3 Volts. Would not run stable at any higher speed probably due to my No-Name PC100 Ram. The fastening clip is a big problem; tough as hell to fasten with just Peltier, impossible with cold plate. I used bailing wire to fasten it to the socket. Next I’m going to try stacking 2 Peltiers.”
Skip reviewed the Tundra (below) and found it lacking; I asked him to send it to me to check out.
The Mushkin Tundra Cooler is probably the worst product I have reviewed yet – it is ill suited as a cooling solution for serious overclocking. In fact, I consider the Tundra to be downright dangerous.
Now I don’t say this lightly; Mushkin has some fine products and don’t take this as a blanket indictment against Mushkin. However, the Tundra is a product an overclocker who wants to push a PPGA to its limits would buy. There is an implied contract between Mushkin and the purchaser of this product as to its suitability for its intended use. For the Tundra this contract is null and void.
The Tundra could not maintain a stable temperature with its peltier at 12 volts. Mushkin, apparently recognizing this, is marketing the Tundra with the peltier running at 5 volts. This is an explicit statement that the Tundra, as originally conceived, is deficient. With its peltier now running at 5 volts, the Tundra was able to maintain my test peltier’s cold-side at a temperature of 59.9 F. Most heatsinks in the Cooler Database will maintain a temperature of between 5 to 25 degrees F. Therefore the Tundra does not come close to performing as well as a conventional air-cooled heatsink! These results were obtained by replacing the Tundra’s puny fan with one from a VEK 12 – the fan that comes with the Tundra is inadequate and it took about 10 seconds to realize this.
The reason I consider the Tundra to be dangerous requires some understanding of how Peltiers can produce a thermal meltdown. If you can’t get rid of the heat generated by a Peltier, it can lead to a thermal feedback loop. As the heatsink heats up and reaches a point where it can no longer dump heat, the heatsink gets hotter. As it heats up, the Peltier’s hot side gets hotter. Then the cold side gets warmer leading the Peltier’s hot side to get even hotter. The heatsink then receives even more heat, which it is unable to dump, and gets even hotter. The cycle continues until some stable point is reached which is no where near what you were expecting. I’ve seen this happen and it’s not pretty.
This vicious cycle was apparent with the Tundra at 12 volts. The heatsink/fan combination is totally inadequate at 12 volts, and barely adequate at 5 volts. For overclocking the Tundra is grossly inadequate. If you are not overclocking and your CPU is putting out minimal heat, the Tundra could be used.
Folks, I’m sorry but the Tundra is a waste of money for any serious overclocking. If I had to choose between putting a Tundra in my system and burning the money I’d spend on it, I’d burn the money.
Skip’s Original Mushkin Tundra Review – 5/4/99
After my Socket 370 cooler comparison, where I beat up on the Mushkin cooler a bit, I got a couple of emails from the people at Mushkin saying that they have made some revisions to this cooler and are looking into more. The Email they sent said they have lowered the voltage to the peltier from 12 to 5 volts and made a fan revision. I have both voltage versions of this cooler, I ended up buying two of them because the first one (Peltier at 12 volts) overheated my Celeron within minutes so I called and they gave me an RMA to return this unit and sent me a new one. Same fan but Peltier wired for 5 volts. I never made it to Fedex to send the RMA so I was charged for the second unit. My fault, they were very helpful and even offered to pay the return shipping. Something you don’t see to often. Mushkin is a great company.
After the email exchange last night, I figured I would make my own revisions so I bolted a 60x25mm 22CFM fan to both units and ran some tests. The room temp for all tests was 84 F, the Internal case temp read 86 F (Hot day here in Chicago). CPU temp was read using my BM6 with the under CPU sensor.
The CPU temp with the 12 volt unit after setting idle (No CPU load) for 10 mins was 92 F. Started running Prime 95 and after only 2 Mins. The CPU temp was 125 F. I also burned my fingers when touching the heatsink. Obviously, 12 volts is just too much for this Peltier/Heatsink combination.
With the 5 Volt unit, setting idle for 10 minutes, the CPU temp was 87 F. I started Prime and after 10 Mins, the CPU temp was 107 F. I left Prime running and watched the CPU temp climb to about 112 then shut prime down. The Temp took about 15 Mins to come back down to 89 F. The heatsink was fairly warm but not HOT like the 12 Volt unit.
I have read about using a cold plate between the Peltier and the CPU so I found a piece of Aluminum that was 1/8″ thick and almost the same size as the base of the Heatsink. I sandwiched the aluminum between the peltier and the CPU on the 5 volt unit and bent the clip so it would latch to the socket.
I started the computer and upon initially loading Motherboard monitor the CPU temp read 105. I left it stabilize and the CPU temp came down to 89 F after about 12 minutes or so. I assume it took this long to cool the aluminum plate. I started Prime 95 and after about 15 minutes of running, the temp seemed to stabilize around 95 F. I left prime run for about 40 more minutes and the temp fluctuated between 97F and 95F.
With the addition of the 60x25mm fan and a 1/8″ cold plate, the operation of this cooler seemed to stabilize a bunch and put the performance on par with the Alpha, but at a higher price. I don’t know if these parts can be added by Mushkin and keep the price at $48. The Alpha still beats the performance of this cooler so, with the drawbacks of added heat to the inside of the case (Peltiers create a BUNCH of heat on the hot side) and the added draw on the power supply, The Alpha at $30 with fan is still my choice for the Socket 370. Hmmmmm, a Peltier with the Alpha????