Background:
I have this board and found that my CPU temperature would idle around 60 and the SAS2 chip would idle even higher, around 85 degrees. Pushing the system at all would put both into temperatures that made me too uncomfortable to call acceptable. I have my board in a U-NAS 810A chassis, so I don't have a lot of mounting options for case fans to do the heavy lifting for me, so I went for fans mounted on the heatsinks themselves.
CPU Temperatures:
For the CPU, I ended up picking up the SNK-C0057A4L ($36) as a drop-in replacement, but the FAN was a little whinny, so I replaced with the stock fan with a GELID Silent5 FN-SX05-40 ($6). So I'm $42 extra in, but CPU temperatures are under control. I was in the low 30's idle initially, so I threw a spare Noctua NA-SRC10 (3-pin LNA resistor) on the fan to get the system a little more silent (I tried this on the stock fan prior to swapping, but it was still whinny even at lower RPMs). Now I'm sitting at around 38 degrees idle, and around 45 degrees with a few VMs running. It's not "amazing" temperatures, but well within acceptable for this platform -- and virtually silent.
SAS2 Temperatures:
My issue is like the OP's, the SAS2 chipset is where I am having a harder time finding a good option. At 85-95 degrees depending on load, I'm just not comfortable with letting that be.
I had an extra GELID Silent5 FN-SX05-40 that I set on top of the chipset for now. This got me down to the 40's, I put a spare Ultra LNA resistor on the FAN and it leveled out around 50 degrees. What I learned is very little air-flow is needed to make a big difference on this chipset. With my ULNA, the FN-SX05-40 is running at 1800rpm and is putting out more than enough airflow to cut the temperature in half.
The problem is that I really don't like having the fan just resting on top of the heatsink like that. I've had to move the box around, and it slid off. So then I had to remove the chassis outer shell, which was a PITA, just to put it back in place. Overall, I would like to find something a little less ghetto.
Has anyone found a good, stock-like solution?
I don't know where to look for a product spec for the heatsink dimensions, and I'm not home this week to measure, but I was wondering if anyone knows of are any drop-in replacements for the SAS2 heatsink like there was for the CPU, but something with a fan (or fan mount option).
Maybe something like this:
Enzotech SLF-40(mm) Memory Cooling - Newegg.com
The product claims "multiple push pin locations for universal mounting on various board
assembly. (hole to hole distance 54.6mm and 59m)." Does this seem about the same push-pin layout dimensions? This option would be ideal for a 40mm Noctua replacement.
Or has anyone had any better luck with another solution that's not just sitting or taping a fan to a heatsink?