Kol's Delid

Nice Work @Kol12

Polo6RGTI said:

Great job @Kol12

Thanks Polo and OldMike! Looks good so far. Will do a little gaming later and then get into some benches later down the track.

Kol12 said:

So CPU temps don't influence the VRM directly, it's more the actual voltage going to the CPU and case temps...

I don't know what a good VRM temp is but before I delidded at 5Ghz the VRM would max at 55C which doesn't seem bad.. I haven't checked to see whether delidding directly affects the VRM yet.

The VRM temp can affect the CPU clocks(therefore CPU temps) by downclocking the CPU if it(the VRM) needs to cool down, but the CPU temps have no effect, only it's power draw(and your video cards) that can cause the VRMs to get too warn.

http://cxzoid.blogspot.com/2015/04/w...-good-vrm.html

So what makes a good VRM?

First of all the VRM has to handle the load. This is very important when overclocking because if the overclocked current draw of your CPU/GPU exceeds what the low side MOSFETs can handle the MOSFETs will burn up. The same happens if you exceed the ripple current of the capacitor bank, You end up with a burnt capacitor. The first is common with cheap AMD and X79 motherboards and reference PCB Nvidia GPUs when pushing the voltage. I've only heard of the second once and that is on the EVGA E-power board when heavily over volting(1.7V) the GTX TITAN-X. You can calculate current capabilities by multiplying the low side MOSFET current rating by the number of low side MOSFETs but with the capacitors you just gotta trust the manufacturer(this is almost never an issue). For a 20% over volt and 20% overclock you will want a VRM with at least 44% more current capability than the stock current draw(~TDP / stock voltage). So for an FX 8350(stock 125W 4Ghz 1.35V) at 5Ghz at 1.525V you would want a VRM that can handle at least 131A. That's 10A more than the typical cheap 4 phase VRM and 31A more than the super cheap 4 phase VRM. Also running VRMs close to spec is bad for them so you'd want 10% head room or 144A.

Now that your VRM doesn't explode when you overclock you need a VRM with low voltage ripple. Voltage ripple basically causes your CPU/GPU to degrade at the rate of the voltage you set however it's maximum clock is tied to the minimum voltage that the ripple creates. So if you set 1.525V and have 25mv ripple you can only achieve an overclock as high as if you had flat line 1.5V while the chip is degrading at the rate that 1.525V causes. To get as little ripple as possible you want the highest number of PWM drive signals coming from the controller as possible at the highest switching frequency possible. So ideally you want an 8 phase controller running in 8 phase mode with a 1MHz switching frequency. The difference this makes is usually minimal but if you're overclocking something with a really high power draw it helps. I also suspect that the stock VRM of the R9 290X has really bad voltage ripple but until I get more equipment I can't test that.

@Kol12 what is the batch number of your CPU?

Nice info Cliff, now I must do calculations.

@Polo I'm not sure, where can I find it?

I think I got a pretty good chip for a stock brought non binned one, I've heard of some people struggling with 4.9Ghz and needing more than 1.3V with the 8700K. I had no issue with 4.9Ghz at 1.29V, I think I will do well above 5Ghz.

How far have you delidded guy's pushed your CPU's? Or is that a secret?

@polo here is the CPU...

Kol12 said:

Nice info Cliff, now I must do calculations.

@Polo I'm not sure, where can I find it?

I think I got a pretty good chip for a stock brought non binned one, I've heard of some people struggling with 4.9Ghz and needing more than 1.3V with the 8700K. I had no issue with 4.9Ghz at 1.29V, I think I will do well above 5Ghz.

How far have you delidded guy's pushed your CPU's? Or is that a secret?

5.4GHz here ....its no secret I posted it last week I think....

Apparently Malaysia manufactured week 30 CPU batches (which mine is) do well in overclocking according to Reddit.

OldMike65 said:

5.4GHz here ....its no secret I posted it last week I think....

Nice!