Overclocking

As cooling solutions do a better job of keeping the CPU at a lower temperature, it is reasonable to expect the overclocking capabilities of the CPU will increase. In each test of a cooler we measure the highest stable overclock of a standard X6800 processor under the following conditions:

CPU Multiplier: 14x (Stock 11x)
CPU voltage: 1.5875V
FSB Voltage: 1.30V
Memory Voltage: 2.20V
nForce SPP Voltage: 1.35V
nForce MCP Voltage: 1.7V
HT nForce SPP <-> MCP: Auto

Memory is set to Auto timings on the 680i and memory speed is linked to the FSB for the overclocking tests. This removes memory as any kind of impediment to the maximum stable overclock. Linked settings on the 680i are a 1066FSB to a memory speed of DDR2-800. As the FSB is raised the linked memory speed increases in proportion. The same processor is used in all cooling tests to ensure comparable results.

Highest Stable Overclock (MHz)

The Enzotech Ultra-X reaches a stable 3.86 GHz - again similar to other down-facing coolers. This is high enough to make the Ultra-X the best overclocking down-blowing cooler we have tested, but it does not match the 3.90 to 3.94GHz measured with the best heatpipe towers.

Many readers have suggested that an auxiliary case fan exhausting air out the back of the case will improve performance of the down-facing fan coolers. As an additional check we mounted an Aero Cool 120mm Xtreme Turbine fan at the rear of the case exhausting air form the case interior. This fan is capable of air flows up to 89 CFM.

The added case fan did cool temperatures by as much as 4 to 5C at stock 2.93 GHz, and 1 to 3C at 3.83 GHz. This did provide somewhat better cooling with the Ultra-X. However, we could not achieve a higher overclock with the Ultra-X with the added high-output case fan. The highest stable overclock was still 3.86GHz.

Scaling of Cooling Performance Noise
Comments Locked

33 Comments

View All Comments

  • Wesley Fink - Thursday, June 28, 2007 - link

    Corrected
  • Barkuti - Wednesday, June 27, 2007 - link

    Too much fuss with all of these new massive coolers. Back in 1995 I purchased a Thermaltake Sonic Tower, which proved to be an incredible performer, best passive cooler IMO. The one being currently available is "rev2", guess it's just a mounting accesories update.

    The cooler comes with a mounting plate for a 12 cm fan, which can be installed on either side. I myself drilled new screwholes on a inner side to be able to install the fan in the center, saving a bit of space. A bit cumbersome to install the fan this way tough. Achieves top performance in this configuration, even with an ultra-low noise fan.
    An Anand's review of this cooler is still missing and I think it's really worth the pain, like a gem lost inside and old chest.

    And with a bit of skill, a little mod and a lot of space you may be able to install three fans on it... Drools about the kind of performance and perf/noise you could get this way, even with just 2 fans...

    Cheers
  • DrMrLordX - Wednesday, June 27, 2007 - link

    Is there a side intake duct or vent that can feed top-down HSFs in your test bed? I'm pretty sure top-downs just don't work well if they can't pull cool air directly in from outside the case (which is why they've done so well in open-air testbeds).
  • vhx - Wednesday, June 27, 2007 - link

    Definitely nice, but there are a lot better alternatives according to the results. Anyways, does anyone know whats up with Anandtech's forums? They've been down for like a week.
  • theprodigalrebel - Wednesday, June 27, 2007 - link

    The forums have been a little iffy of late but they most certainly haven't been down all week. They just had an update of the forum software and there were a few minor outages here and there - Opera users had some problems, so did IE users. Did you try deleting all forums.anandtech.com cookies? It should work.
  • Wesley Fink - Wednesday, June 27, 2007 - link

    The LATEST NEWS at the top of our AT Forums Log-In page:

    "Clear your cookies... - 06/24/2007 01:17 PM
    We recently updated our forum software to fix a number of issues. As a result, some users are having problems using FireFox on the forums.

    The fix for this is to delete your forums.anandtech.com cookies.

    We recommend that all members delete their forum cookies, though we haven't run into any technical issues with this in other browsers.

    Thanks for your patience while we continue to improve the forums."
  • Pirks - Wednesday, June 27, 2007 - link

    I've got myself A cooler master geminII and run it in passive (fanless) mode, and no fan on my passive mobo chipset heatsink as well. finally I've got a silent PC! my wife thinks my computer stopped working now, hehe :) no overclocking of course but who needs it for games anyway. I'm getting high framerates with S.T.A.L.K.E.R. around 30-40 fps and I'm happy. who says you need a mac to get a silent computer? who says gaming PCs are noisy? just ignore those noobs, they know nothing
  • deadseasquirrel - Wednesday, June 27, 2007 - link

    but it seems, at least according to this review, that it is not worth the price for the performance you get. Can anyone else see a better price/performance cooler than the Scythe Mine Rev B? For $38, with fan, and pretty quiet, it seems like a good choice. Oh, and are the forums down or am I having browser problems?
  • kmmatney - Thursday, June 28, 2007 - link

    I have a Scythe mine and am happy with. It's a good combination of price, low noise (its nearly silent) and good cooling. I don't know if I'd recommend it for extreme overclocking, but for stabdard overclocks it is great.
  • Goty - Wednesday, June 27, 2007 - link

    Based on the little knowledge I have about the inner workings of heatpipes, wouldn't the lower heatsink on the X-Ultra lower the efficiency of the heatpipes (where heat transfer to the main heatsink is concerned) and thus the whole cooler?

Log in

Don't have an account? Sign up now