EVGA X58 SLI LGA 1366 Motherboard Review

Heat & Acoustical Testing

The heat and acoustical testing normally concentrates on the north bridge and its cooling solutions. With the north bridge playing a smaller role in the X58 game, we decided to us this section to really look at the PWM cooling of the EVGA X58 SLI. We also found out that the NB temperature sensor does not actually report the NB temperature in Windows, only the BIOS. This means there is no accurate way for measuring temperatures of the NB right now, EVGA is working on a BIOS option to enable NB temp reading in Windows, which made the PWM focus a no brainer for us.

With heafty power hungry i7 quad core CPUs populating the LGA1366 socket, the PWM area of the motherboard is put under great stress. Because of this there is a substantial amount of heat being generated and despite the large heat sink EVGA has gone with on these components, the PWM temperatures are still rather high. Let's first look at exactly what we are dealing with.

The PWM MOSFET heat sink is a fairly simple design that looks a lot more elaborate than it is. There is a single long heat pipe that runs the length of the MOSFETs and then angles up on each end to connect with the cooling fins that dissipate the heat generated by the components it sits on. Again, this is very simple but seemingly effective. The best part of this design is that it is seperate from the NB/SB heat sink and swapping it out for water cooling or another air cooling solution only requires it to be removed. This is what we are looking at with the heat sink removed:

The MOSFETs used by EVGA on this X58 SLI are not your standard D-Pack surface mount MOSFETs. Instead, EVGA has used a high efficiency Renesas R2J20602 56-pin leadless QFN package MOSFET. These integrated driver-MOSFETs provide low voltage stability and switching frequencies up to 2MHz. The one specification we were unable to locate on these particular parts are their rated temperature. So we still don't know what a safe operating temperature might be for them. This brings us to the subject of cooling the PWM.

As of right now, there are no alternative cooling solutions so we had to come up with some options our selves. The only thing we could ascertain is using the tried and tested Swiftech MC-14 solution. We have been using MC-14s on PWM MOSFETs for a long time and always had great success. Unfortunately, this didn't work out so well because the MC-14s didn't fit. Shame on EVGA for not allowing us to use our favorite Swiftech heat sink. Instead, we had to resort to Enzotech MOS-C1s. These are quite a bit smaller and we weren't sure if they would even be able to handle the heat from the PWM MOSFETs. Here are a couple photos of the setup with the Enzotech MOS-C1s and the problem with the MC-14s.

We can now look at the results of the load testing of each setup. We also threw in the results of simply changing out the thermal pad on the existing cooler with that of Sekisui #5760 thermal tape. The load testing was done with one hour of OCCT Mix using Everest Ultimate to chart the PWM temperatures throughout testing. Ambient temperature of the room was a controlled 23C~24C as measured directly above the setup with an Extech TM200 digital thermometer. Here is how the three different PWM cooling solutions shook out:

We honestly can't say this is what we were expecting. It isn't often that a stock PWM cooling solution is going to perform as well as one that is slightly tweaked by an end user, but that is definitely the case here. We have to admit that the competition, Enzotech MOS-C1s, weren't really the toughest of competition seeing as they only covered a portion of the large MOSFET ICs. We really would have liked to get Swiftech MC-14s or Enzotech BMR-C1 heat sinks on there but the space just wouldn't provide that luxury. We also thought that changing out the thermal pad for high quality thermal tape may have done some good but that clearly hindered performance. This is likely due to the base of the heat sink not being completely flat and contact not being perfect on the ICs.

With the thermal pad used, the contact on all ICs is even and complete as is the contact on the base of the heat sink. We still think there are better cooling solutions for this PWM but as of right now, stock is where it is at for the EVGA X58 SLI.