My DDR3 caused my CPU temps raising high. Any solution?

[shadowillusion]

My Mobo: Gigabyte H55-USB3

My CPU: Intel i5-750

My DDR3: Corsair Dominator TR3x6G-1600C8D which has 1600mhz when XtremeMemoryProfile enabled...

Some thoughts, correct me if I wrong:
- i5-750 default memory controller speed is 1333mhz... So my gigabyte mobo must tweak it to 1600mhz...
- when I enable XtremeMemoryProfile (1600 mhz 8-8-8-24), my CPU VCore is 1.28V (idle) to 1.264v (100% load), temp is 56C (idle) to 99C (100% load)
- when I disable it (1333 mhz 9-9-9-24), my CPU VCore is 0.88V (idle at 1.2Ghz) to 1.184v (100% load), temp is 40C (idle) to 78C (100% load)

Some facts:
- I already reseated my CPU, even replace my CPU and motherboard with the new one from the shop, still the same temp
- 6 fan cooled case. No problem with the case
- Fan maxed out at 2500RPM++. No problem with the fan
- Stock fan, stock paste, stock frequency no OC

Question:
1. Is that temp when XMP disabled (40C (idle) to 78C (100% load)) is normal? If not, do you know why and how to solve it??
2. Is that temp when XMP enabled (56C (idle) to 99C (100% load)) is normal? If not, do you know why and how to solve it?
3. Do you think that I need undervolting? If yes, how?
4. Do you think that I need another solution (such as maybe kick-ass hydrogene cooling? )? If yes, please mention?

 

[tkgclimb]

I have one theory but since I've never oc'd an intel cpu before it might be convoluted.

CPU frequency is bus speed x multiplier. I think what is happenning is when you set the memory to run at 1600mhz with the motherboard, you are changing the i5's default memory controller speed to 1600 from 1333 like you said, but I think the board or you is also changing the default HT or bus speed of the 750 from 1333 to 1600 in the process, or some denomination of this amount (like 133 to 160, like i said i'm bad with intel cpu's).

By doing this you are accidently overclocking it (cpu) and the motherboard is automatically stepping up the voltage.

Or maybe it has something to do with a turbo boost complication.

I've never heard of hydrogen cooling, you probaly mean nitrogen cooling, which is extremlly unpratical. If you really want your temps lower go H2O

 

[saint19]

Hi newcomer and welcome to the Tom's hardware forum.

Just for curiosity. What cooler do u have?

 

[simon12]

He states stock fan stock paste stock frequency.

 

[saint19]

^Right, Intel and AMD FBS are 1333 if u select XMP for 1600 u need OC the CPU and that means more power use, more voltage and more heat.

 

[shadowillusion]

Best answer selected by shadowillusion.

 

[wolfram23]

You need to buy an aftermarket cooler, the temps are "ok" at stock but at 160mhz you NEED to get aftermarket, temps at 100C are NOT good for the CPU, which is rated for 72.5C max.

The "Best Answer" is right. Here's my suggestion: Instead of enabling XMP, simply keep your settings all at stock. Then, raise DIMM/DRAM voltage to 1.65V. Then, go into manual timings for the RAM, and lower them to 7-7-7-21. Since the RAM is rated 1600 CL8, you might even get away with timings of 6-6-6-18 although that might be pushing it. I run my 1600mhz CL8 RAM at 1400mh CL7. You might consider doing that as well, just bump the Base Clock to 140 and leave voltages on auto. This will add significantly less heat on the CPU since it's only a 7mhz base clock bump.

Just FYI, I have a Zalman CNPS10X Extreme and running 4ghz no turbo (i5 750), my idle is 42C and max load is 74C - so you can see a good cooler makes a world of difference.

And one other thing, if you have 3 sticks of RAM, you're doing yourself a disservice. i5 750 can handle dual channel RAM, only i7s on X58 mobos can handle triple channel. By using 3 sticks of RAM, you're forcing single channel RAM which is not as good as dual channel, so you're slowing your PC down. You need either 2 or 4 RAM sticks to run dual channel.