VGA VRM Heatsinks. Important?

I am trying to get an idea here of when one should be concerned about installing VRM heatsinks on their video card(s). Here is what I got:

After I lost some of my last system to condensation from the vapochill, I decided to migrate all the surviving parts on over to my unused 4U rackmount case and build a "New" gaming system. In order to keep costs down I decided to stay a few generations behind in technology and just overclock the hell out of everything.

For my two 768MB GTX460s, that max stable overclock turned out to be 900Mhz core and 1050 on the RAM. With everything fine tuned I was able to dial in these clocks stable with a 1.087 core voltage on card one and 1.1 on card two. I am running the stock EVGA coolers with a few simple modifications and also a "secret ingredient" and OCCT load temps seem to be 61C for card 1 and 55C for card two. I actually got the first card to hit 930Mhz on 1.087 which surprised the hell out of me, but when the second card still proved unstable at 910Mhz with a hefty 1.125v core I decided to abandon hopes of anything above 900Mhz and didn't push the first card any further.

Given the fact that I believe these are excellent temperatures for the overclock involved on the stock cooling I am left with the last concern of the VRMs. I don't want everything to be fine and dandy for a month or two then be in the middle of Crysis 3 and end up blowing a VRM off the board.

Would everyone here be confident in saying that the voltage mods warrant VRM sinks?

I've seen plenty of folks running only a fan over their vrm using the H60/620 mod to cool the core.
I'd like someone more experienced to chime in though, that's something I may try eventually.

Airflow is definitely not an issue, and actually the reason I was able to achieve these clocks/voltages with such great temps on the stock cooling.

To give everyone an idea of just what we're dealing with, here is what I did.

I removed the coolers from the cards, used rubbing alcohol to clean the crap silicone paste off and replaced it with AS Ceramique 2. While the coolers were off I noted a very rough machined surface on the copper plate that contacts the GPU so I lapped them. I also did some investigating into "High flow exhaust brackets".

http://www.evga.com/Products/Product...M020-00-000171

The general review consensus was that they lowered temps by 1 - 2C. I was not prepared to pay $20 + shipping for this however I did see an opportunity to get an even better solution out of the stock brackets. I whipped out the dremel and this is what I ended up with:

http://i20.photobucket.com/albums/b2...ps4eea98cd.jpg

As you can see I completely removed the "grill" area of the brackets and left only a thin frame completely opening up the cards for exhaust flow.


Also at the front of the case where the video cards are there is a 120mm intake fan rated at 50CFM. Now for the "secret ingredient" I mentioned. My friend had a 92mm vantec tornado he was not using due to the high noise levels and gave it to me for free. The mid mount "fan bar" of my 4U case used 80mm brackets so I cut a piece of aluminum off the door from my old case and made a 92mm bracket for it. I mounted it halfway in the case directly in front of the video cards. This made the biggest difference of a 12 - 15C reduction in core temperatures. I have speedfan set to idle it at 30% when the system is not under load and it is very quiet. I can peacefully sleep 10 feet away from the system. Idle temps are around 34C on card 1 and 28C on card 2. As soon as the GPU temperature reaches 50C speedfan throttles it up to 75%. The way the intake fan, tornado fan and the video card exhaust is setup is almost like a wind tunnel effect around the video card area of the case. I actually think the temps would be a couple degress lower if the front intake fan wasn't blowing it's air over a 4 disk raid array (Non SSD).

http://i20.photobucket.com/albums/b2...pse160d1b9.jpg
http://i20.photobucket.com/albums/b2...psdc76cd9a.jpg

You should be fine as long as you have good airflow across the VRMs (which it appears that you do)

Strange case that is...is that a server type case or what? Nice 38mm thick fans :p

Quote:

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Originally Posted by Ivanlabrie

Strange case that is...is that a server type case or what? Nice 38mm thick fans :p

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It's a 4U case that I grabbed back in 2008 and planned on using to build a 2x dual core opteron server for fun and a bit of dabbling in the server world. The supermicro motherboard I had sat in this case for the past 5 years and when my vapochill fried the cpu/board combo and almost took out one of my 460s I decided to start anew and move everything on over since the lian-li case had been cut and hacked up one too many times over the years, plus I had grown unfond of the UV green/blue theme I designed it around.

airflow was a bit of a problem but I managed. That little sunon fan is powerful and also speedfan controlled :p:. I also added 4 60mm intake fans to the lid. Honestly this case had a horrible design for exhaust airflow. 1 60mm vs two 80mm at the rear but I've noticed that alot of 4U cases today don't have that bar mounted halfway in the case that you can hang fans from. That simple bar has proved to be very versatile. I'm planning on hanging an M184 radiator from it in a push/pull setup where the two 80mm fans are now.

Quote:

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Originally Posted by CrazyNutz

You should be fine as long as you have good airflow across the VRMs (which it appears that you do)

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I was thinking of cutting a portion of the plastic shroud out at the back of the cards to improve VRM airflow.