This is the first PC I've built in a few years, so I have an Asrock 960GM/U3S3 FX that I've had about 2 weeks now. It has a fx-8120 running stock, with stock HSF.
I have noticed that after a few minutes Prime95 on all 8 'half cores' , the cpu will throttle back. (To be fair, it was over 85'F in the house: good california heat!)
I suspected VRM overheating. I kept stock speed, reduced voltage to 1.2, and put a fan directly over the mosfets. Throttling reduced, and I think it might even be gone completely.
I did some research, and read many things that I wished I came across before I bought the board. When I last build a PC, cpus took <80 watts, nobody worried about mosfets exploding, and even my cheapo MSI and ECS boards from back then are still fully operational; they are just pathetically slow compared to the new stuff.
I emailed ASRock support, and they said the board really can handle 125W, and that the board will throttle back if the VRMs overheat, and that putting a fan on the mosfet was the correct option. The board seems 3+1 though, it's got 4 pairs of transistors, and 4 chokes by the CPU, and then 1 other choke & transistor set near the RAM.
Should I believe them? If I go and put heatsinks on the mosfets, and point a fan on them, should I believe a fx 8120 stock (or fx-8120 at fx-8150 speed) should be 'safe?' Of course I won't run prime95 24 hours a day, but when I do hit those moments in peak load (video encoding, games, etc), I don't want to let the magic smoke out of the transistors. I suppose throttling is better than exploding!
I did a little further research: I looked up the part number for the transistor/gate driver pairs on the board, and each device is rated for 50 watts. So I'm thinking 50 watts x 3 = 150 watts, so a 125 watt processor at stock, with cooling should be 'fine'. Is 25 W headroom 'good enough'? I have no idea what the effecency of the whole VRM system is though: If the vrm components are getting warm, they are dissipating heat/energy, so a CPU pulling 125 watts will need >125 watts through the transistors. If
I read through some additional items on this forum, and even the 4+1 phase ASUS M5A88-M which claims 140W has trouble feeding the 8150 stock power requirements. I also hear sometimes you get an ASUS board with out-of-date BIOS, and you need to immediately RMA it so they can reflash it to recognize your FX chip.
What would you do in my situation?
1. Keep the existing board, add heatsinks, fan directly on vrm, keep at stock. And get a better CPU cooler.
2. RMA the board, pay newegg's restocking fee and get something else. (And what's the something else?) I would like to keep sata3 usb3 if possible.
Thanks!
I have noticed that after a few minutes Prime95 on all 8 'half cores' , the cpu will throttle back. (To be fair, it was over 85'F in the house: good california heat!)
I suspected VRM overheating. I kept stock speed, reduced voltage to 1.2, and put a fan directly over the mosfets. Throttling reduced, and I think it might even be gone completely.
I did some research, and read many things that I wished I came across before I bought the board. When I last build a PC, cpus took <80 watts, nobody worried about mosfets exploding, and even my cheapo MSI and ECS boards from back then are still fully operational; they are just pathetically slow compared to the new stuff.
I emailed ASRock support, and they said the board really can handle 125W, and that the board will throttle back if the VRMs overheat, and that putting a fan on the mosfet was the correct option. The board seems 3+1 though, it's got 4 pairs of transistors, and 4 chokes by the CPU, and then 1 other choke & transistor set near the RAM.
Should I believe them? If I go and put heatsinks on the mosfets, and point a fan on them, should I believe a fx 8120 stock (or fx-8120 at fx-8150 speed) should be 'safe?' Of course I won't run prime95 24 hours a day, but when I do hit those moments in peak load (video encoding, games, etc), I don't want to let the magic smoke out of the transistors. I suppose throttling is better than exploding!
I did a little further research: I looked up the part number for the transistor/gate driver pairs on the board, and each device is rated for 50 watts. So I'm thinking 50 watts x 3 = 150 watts, so a 125 watt processor at stock, with cooling should be 'fine'. Is 25 W headroom 'good enough'? I have no idea what the effecency of the whole VRM system is though: If the vrm components are getting warm, they are dissipating heat/energy, so a CPU pulling 125 watts will need >125 watts through the transistors. If
I read through some additional items on this forum, and even the 4+1 phase ASUS M5A88-M which claims 140W has trouble feeding the 8150 stock power requirements. I also hear sometimes you get an ASUS board with out-of-date BIOS, and you need to immediately RMA it so they can reflash it to recognize your FX chip.
What would you do in my situation?
1. Keep the existing board, add heatsinks, fan directly on vrm, keep at stock. And get a better CPU cooler.
2. RMA the board, pay newegg's restocking fee and get something else. (And what's the something else?) I would like to keep sata3 usb3 if possible.
Thanks!








