AS5 or MX-3

I have a tube of AS5 I've been using for a couple years, it's still about 30% full. I could buy a tube of MX-3 for about $20 and receive it in 1-2 weeks. Is it worth ordering the MX-3? I plan on doing the cpu and gpu.

 

No, not worth it. Just keep using what you have until it runs out and then splurge for something really nice.

 

Seconded what Trottel said.

 

ive always just used up what i had then ordered the best i could the next time. but in this case i just cant say go ahead and use up a paste that is as conductive and dangerous to a notebook in a notebook thread. ultimately its up to you but if i was in your situation i would order something safer for use in notebook computer components. As5 honestly isnt that great anymore considering the safer faster curing alternatives that work just as good or better now available.

 

Ok, so two yay and one nay so far.

 

People always bring up that AS5 is "conductive" (it isn't) and that it is dangerous, yet it has been a market leader for years and nobody has had any problems with it. This fear comes entirely from the fact that the specs list it as very slightly capacitive, even though there is no risk. People used to not make a stink about it for several years after it was released because nothing else could match it, but when new products came out that rivaled or surpassed it, people all of a sudden used this as a negative in their decision of what thermal paste was the best and began warning others about the "danger." There have only really been two possible cases where AS5 may have caused permanent harm. They involved cases where AS5 "mysteriously" got smeared into the CPU sockets, leaving the motherboards dead. Moral of the story is leave the TIM on top of the CPU, not underneath it. AS5 wouldn't have been the undisputed best thermal paste for so many years and still a valid contender for the top spot if there was any danger involved in its use. And on top of that we would actually hear AS5 horror stories if there were any.

Since safety concerns are wildly overblown and AS5 is as safe as a stuffed animal, you can really only focus on its performance. It still holds very well compared to top thermal pastes formulated much more recently. There really isn't any reason to go out and spend money on something new when there is already AS5 there to get the job done.

 

But being non-conductive means thermal paste (like MX-2) can be applied in places besides CPUs, where there are exposed circuitry such as on VRMs and on places that would be very hard to clean off such as on exposed memory. I have done so on ghetto repairing my desktop 8800GTX. Works much better then the crappy Arctic Cooling thermal pads too.

 

You used paste as a thermal pad? Wouldn't that be way to thick?

 

Another vote for using what you already have.

FYI I use MX-2 on my vram, spreads just right and it's really easy to clean off of the ram chips.

 

You only need a small bead to secure the sink. If it's not sticking, add some more. The thermal pad I was referring to were the thin adhesive on the underside of Arctic Cooling's ramsinks. Single use only and sometimes it doesn't stick on the first go. Not much can be done about thermal pads.

 

But it has to go EVERYWHERE! Isn't moar better? I heard on the interweb that you have to put it on both sides of the chip, just like mustard on a sandwich. And more mustard always tastes better, so slather it on and use the whole tube, amiright?

Not entirely. AS5 seems to have a bad habit of drying out and getting crackly after maybe two years of constant power cycling. I never noticed it on my desktops since they were always-on or at least never set to sleep on idle like many laptops are. Since I started applying it to machines with heavy power cycling, it's been a minor issue that crops up in the laptops I use for longer than that or that I power on/off heavily (especially my netbook).

Yes to the "small bead". No to the "add some more". Anything more than a translucent layer and performance plummets. AS5 isn't meant to be used with unsecured sinks, and using that much just to make it sticky is somewhat going to defeat the purpose of having ram sinks at all.

 

slightly off topic but is IC Diamond 24 Carat a good thermal compound?

 

Yes, it is one of the top five.

 

I never said I used AS5 for my ramsinks. And a small bead is sometimes just too thin to even cover the entire memory chip, let alone stick.

 

I had the opportunity to test both AS5 and MX-3. MX-3 is the winner. It shaved off 2*C from load. Plus MX-3 isn't conductive which is a plus.

IC Diamond 24 causes scratches on the heatsinks but it's really good.

 

My bad, read that wrong.

Did you read trottel's post? AS-5 is not electrically conductive. At worst it is slightly electrically capacitive, but that is not at all the same thing. The problem is that Arctic Silver was one of the first companies to talk about being THERMALLY conductive back in the day, and people with took their little bit of knowledge and assumed that conductive is conductive. You could smear any Arctic Silver variety all over your electronics and not have a problem as long as you don't interfere with a connection.

As far as that 2*C diff, that's roughly what I've seen in the past as well, but it's not enough for me to dump the AS5 tube I've got (and can't seem to use up after 4 years). Both are usually an improvement over stock regardless, subject to user application variance.

 

This thread reminded me that I need to reapply thermal on my cpu. I did some price checks for the MX-3, and found something worth checking out:

https://www.ewiz.com/detail.php?name=FAN-MX3&title=ARCTIC-COOLING-MX-3-Thermal-Compound

They're selling the 4g MX-3 for $10. Shipping costs might differ for you (was $2 for me), but it should still be cheaper than $20 total if you're in the states. At this price, it would be worth a test to see if it's an improvement over the AS5. I myself have been using AS5 for over 5 years, and I figured it's time to try out something different.

FYI, I found the retailer through Arctic's directory, so it should be legit.

 

I honestly don't think there is a practical difference between the top-of-the-line thermal pastes. There may be initial differences in temperatures, but in the end it becomes a matter of how quickly your heatsink can dissipate the heat it absorbed (nothing to do with the thermal paste) rather than how quickly it can absorb heat (which has everything to do with the thermal paste used).

Physically, the thermal paste will determine how effectively heat is transferred from the CPU to the heat sink. Arbitrarily, let's say that AS5 is 95% effective and MX3 100%...like really, it just means that the heatsink using MX3 will heat-up/cooldown (slightly) faster than the setup using AS5. The maximum and minimum temperatures however should be the same (theoretically), as they are determined by the performance of the heatsink, not the performance of the thermal pastes (which have no cooling capacity).

Thermal pastes would only become important in affecting max/min temperatures if one was to be so inefficient at transferring heat that the CPU would start to heat up faster than the heatsink can, to the point of overheating.

Obviously AS5 is not that bad.

 

Actually thermal pastes do affect temperatures. Think about when you are in bed and you put on a sheet. You will warm up to a point where the heat being released from out of the blanket equals the amount of heat being released by your body. If you put on a comforter, you will be a lot warmer at the equilibrium point. It is the same thing going on. Of course, these thermal pastes are already very efficient. The difference is very small between the top 5 or so, either within the margin of error or within the range that it varies with each application. The improved thermal transfer abilities new pastes are chasing are smaller and smaller.

 

Thermal paste has got to the point that it pretty much has the same effect as if the chip were physically attached (perfect contact). The difference between the top pastes are usually in fractions of a degree, I just went with MX-3 because it's fairly thin compared to some pastes, it's non conductive or capacitive, has no cure time and also it won't crack up like AS5 will if you leave it for a year or so.

 

The only problem I have with your comforter/bed analogy is that those items on the bed serve a completely different purpose, and the results reflect that. Makers of comforters or whatever pay no attention to heat management when making comforters - comforters are there for aesthetic/comfort reasons. Hence, it's no big deal if they do affect the "thermoequilibrium" (and they do).

Thermal pastes on the other hand are designed with heat management in mind. Their sole purpose is to fill in microscopic pockets of air in the contact surface between the heatsink and the CPU to maximize transfer of heat. In other words, they are designed to not affect thermoequilibrium, but rather how quickly it is reached. In fact, pastes would only affect the equilibrium negatively by inefficient transfer of heat, as you can't have greater than 100% efficiency. Thus, the perfect thermal paste would never "cool" a CPU by itself without a heatsink.

Outside of its negligible contribution to heat conductive mass (yes, that 0.01g of applied paste means an extra 0.01g for the heatsink), thermal pastes never cool a CPU. In fact, if the heatsink is hotter than the CPU (as may be the case if the heatsink is shared with the GPU) than the ideal paste would actually transfer heat from the heatsink to the CPU.

 

You are misunderstanding. The sheet/comforter analogy is in regards to how well a paste facilitates heat transfer from the cpu to the heatsink. The comforter would be like a generic paste and the sheet would be like one of the premium pastes. In both cases when the heat transfer reaches an equilibrium, the same amount of heat will be radiated from the bed as is radiated from the person sleeping. However, when using the sheet, the temperature of the person will be much lower than the temperature of the person using the comforter. The more insulating comforter needs to reach a higher temperature gradient before reaching equilibrium. This is the same thing that happens with thermal pastes and, all else being equal, why some give different temperatures than others.