Overclocking Help / Blog

[andyb]

This runs against the grain of the mindset of most SPCR fans, however I have no issues with using more electricity, generating more heat and having to keep the system cool and quiet.

My setup is as follows.

I have a 45nm "Propus" Phenom II X4 840 (this is not a "true" Phenom as it has no L3 cache). By default this CPU runs at 3.2GHz and has a clocked multiplier and rated as a 95 Watt CPU.

I have a kit of 2x 4GB 2,000 MHz rated DIMM's, Corsair XMS 3, the "official" timings at 2,000 MHz are 9-10-9-27 @ 1.65v This RAM is specced for Intel systems I understand, and I may not be able to get this RAM to run at that speed with those timings.

The motherboard is the Gigabyte 880GMA-USB3 which is a pretty solid motherboard, although not specifically designed for overclocking it should cope well with such activities to a reasonable degree. The manual says that the RAM can run at 1,866 MHz, however the setting in the motherboard actually allow me to run the RAM at 2,000 MHz. That is where other forum member come in.

I have overclocked many different systems over the years with varying degrees of success, with my best achievement of a staggering 50% stable OC, I am not expecting to get anywhere near those giddy heights.

Things have changed somewhat from my previous experiments, specifically that there are so many more options than there were a decade ago. There are many busses, many multipliers and several can be locked so as to not adversely affect other options.

What I want to know is what setting to change, what not to touch and how to truly identify stability - which is still the most important concern, I don't want to have the fastest PC on the planet that crashes every half hour - I want to have a faster PC that never crashes due to overclocked hardware.

Also note that cooling is really not an issue for either the CPU or Chipset.

Here is a brief list of things that I have tried/tested so far.

Before my shiny new RAM turned up I though I would test a large increase in the "CPU Bus speed", I set it a 250 MHz from the usual 200 MHz, I dropped the "CPU multiplier" so the CPU was not overclocked, and I dropped the "RAM multiplier" so that the RAM was not overclocked either. Success, 14-hours of Prime 95 on 4-cores in a warm room, followed by some Skyrim and general use of the PC.

As you may already know I essentially didn't do anything out of the ordinary, or even stress the system at all (I don't know if that was trivial or a small miracle). What I did do was to essentially prove that in theory I could run my RAM at 2,000 MHz because that bus speed and multiplier combo allowed it as an option in the BIOS.

Since getting the RAM I did just that, but it refused to work at those very tight timings, however it did work at looser timings of 11-11-11-27 @ 2,000 MHz. After about 30-minutes of Prime-95 whilst watching the BBC News live stream I had a software crash that didn't resolve itself. No damage from a forced shut down to the OS.

As I dint know what the actual cause of the crash was (it could have been the crappy "flash player" and not an overclock issue at all) I thought I would drop the bus speed to 233MHz and the RAM speed to 1,866 MHz which is what Gigabyte suggest is the fasted supported RAM speed anyway - this seemed to be more cautious but more likely to be stable, so I also threw a small CPU overclock in the mix as well, the CPU is currently running at 3,495 MHz a 9.2% OC, not exactly impressive but it seems to be stable - although I have not pushed it yet. The machine has been in this state for the last 2.5 hours, but I have not run Prime 95 or played any games as I have been busy building someone a server - Prime 95 will return later.

If you have any suggestions or expectations for me please feel free to air them, especially if you have a current AMD system that you have overclocked.


Andy

[andyb]

UPDATE:

I ran Prime 95 overnight (11+ hours), the PC seems to be stable with a relatively minor overclock of 300 MHz with no adverse heat effects, and no increase in voltage.

Additional update:

Additional small CPU OC, now 3,611 MHz (233 x 15.5) default voltage.

Prime 95 x 4 set to low priority so that it does not affect me playing Skyrim, which doesn't use more than 60% CPU usage anyway........... as it turns out, its not a smooth gameplay as it usually is (not totally smooth to start with), still, I will leave Prime 95 running - Core temp at 55C with the CPU fan running at 80% (1300 rpm) which is higher than it usually runs at, probably partly due to the extra 120W that has just been thrown out bu the graphics card for 5-minutes, I expect to see the CPU temp drop a little and as such the CPU fan spin more slowly.


Andy

[andyb]

The last update of the day.

After an hour or Skyrim and Prime 95 (2x cores) running for an hour, Skyrim dropped out, when I re-loaded it I got the "Bethesda" logo in all sorts of horrible colours and then it shut, I re-tried a couple of times, the same thing happened. I went to look up the issue on the internet, my hunch was a video-driver crash. Firefox shut the moment it was started, and strangely Crome which was already open was still there but with no toolbars - only HTML showing.......

For the sake of proving whether it was caused by overclocking or not, I bumped the clock speed up again, I ram Prime 95 on all 4 cores, it lasted a few seconds before a BSoD. To me that proved that the CPU was on its limits of stability at that clock and voltage, so I dropped the CPU clock back to 3,611 MHz and bumped the CPU voltage up by the smallels allowed in the BIOS (0.025v) so far so good.

After running Prim on all 4 cores again for 2-hours before adding over an hour of Skyrim to the mix everything is OK.

Cooling still has not been an issue, the room has got warm, the CPU temp has hit 56C and the CPU fan has hit a huge 1,400 rpm (88% under Speedfan). As far as this is concerned, its not even an issue worth mentioning, the CPU fan speed has not hit 100% AND the CPU temp has not even reached 60C, so there is further to go there as well.


Andy

[andyb]

My CPU cores according to SpeedFan have recently hit 61C with the CPU fan running at 100% (windows closed room temp - uncomfortable).

To be fair, this is whilst running Prime 95 on all 4 cores (for 6-hours and during that time, Skyrim for 1-hour earlier at the start, and just finished another 2-hours), since then the CPU temp has dropped to 58C, and the fan speed to 96% (1415 rpm). When I open the windows I expect the temps to drop by 5+ C within minutes - bear in mind I am "stress-testing" vs "real-world testing".

Opening the windows dropped the CPU temp by 4C in 15-minutes, I expect that temp to drop another 2-3C before settling.


Andy

[frenchie]

Cool write up.
Since your temps are so low, why don't you bump the voltages as high as you're willing to go, and then up the clocks as high as it will go without crashing...
How about bumping the memory voltage a bit too ? That might help the bus stability no ?

I'm also fairly new at overclocking but it's fun

[andyb]

Cool write up.

Thanks, its seems to have turned into a blog rather than lots of people offering help and advice, but that doesn't bother me too much as it might help other people and its not like SPCR forums are overflowing with overclocking enthusiasts.

Since your temps are so low, why don't you bump the voltages as high as you're willing to go, and then up the clocks as high as it will go without crashing...
How about bumping the memory voltage a bit too ? That might help the bus stability no ?

That is my main problem, I don't really know what is safe and what is not, different overclocking enthusiasts say all sorts of different things. Voltage is my main concern, a simple overclock is not likely to cause any damage to the CPU, voltage increases are far more likely to do damage, the same goes for the motherboard and RAM.

The RAM in particular is an odditiy, as far as I can tell its not easy to get an AMD CPU to run with tight timings and high clock speed, and that is mostly to do with the integrated memory controller rather than the motherboard. I knew the RAM was overkill even for my overclocking targets, but it does mean that the RAM is capable of anything that the CPU can ask it to do which means that the RAM itself wont actually be overclocked, if anything it will be underclocked - my plan was to get a good RAM clockspeed and then try to get better timings and perhaps even drop the memory voltage down, all whilst running the RAM within its capabilities.

Ideally I want to hear from someone who has overclocked (successfully) a Phenom II or an Athlon II, as that will give me some sensible guidelines and expectations.

I'm also fairly new at overclocking but it's fun

So am I in a way. I haven't really done any for 7 odd years. That 50% OC BTW was in the year 2000 on an "Abit BP6", quite a legendary motherboard. I was running an SMP system years before anyone else I knew, and only finally retired the poor motherboard and CPU's around 2004/5. It has its own Wikipedia page http://en.wikipedia.org/wiki/ABIT_BP6 I was running a pair of 400 MHz Celeron's at 600 MHz, it was at the time so awesome to be able to rip the music from 2 CD drives at a time, or to burn a CD whilst writing a word document, almost unheard of 12-years ago and it was pretty damned cheap.

The BP6 was the only motherboard of its type, Intel immediately modified all of their Celeron processors from being able to run in SPM mode because so many people bought a BP6 + 2x Celeron processors that it was seriously hurting their sales of their more expensive CPU's.


Andy

[cmthomson]

You probably already know this, but I'll mention it for the thread: power goes up linearly with clock speed, but with the square of the voltage. That is, P=C*V*V. So only boost voltage if you have good cooling.

I've been an Intel overclocker but not an AMD one, but based on what I've read, AMD CPUs won't tolerate high temperatures as well as Intels do. I've run several Intel CPUs at very high temps (some of them for over three years), some up to 80C. Don't do that to an AMD CPU!

[frenchie]

And sometimes just a tiny voltage boost will get you stable for a minimal impact on temps.

[cmthomson]

And sometimes just a tiny voltage boost will get you stable for a minimal impact on temps.

True enough. My current rig was stable at 4.4GHz with only a 0.04V boost. I run it now at 4.2GHz with a 0.01V undervolt.

What I was warning against was the kind of stuff you see on the extreme sites, with people running chips with a 1.25V design point at 1.45V using liquid nitrogen cooling. They win a benchmark contest, but their $300 CPU lasts about a week...

[quest_for_silence]

That is my main problem, I don't really know what is safe and what is not, different overclocking enthusiasts say all sorts of different things. Voltage is my main concern, a simple overclock is not likely to cause any damage to the CPU, voltage increases are far more likely to do damage, the same goes for the motherboard and RAM.

...snipped out...

Ideally I want to hear from someone who has overclocked (successfully) a Phenom II or an Athlon II, as that will give me some sensible guidelines and expectations.

I don't think it can help you a lot, due to the different CPU, but this is what I did: that system is running fine and stable since then.

viewtopic.php?f=28&t=60141&p=523663#p523663

However, broadly speaking, AFAIK usually overclocking exploits are noticeably more limited by RAM and mobo capabilities (power circuitry and BIOS), rather than by the CPU itself (I'm not referring to contests, shows, or any oc'ing tournaments/races/parties).

[andyb]

Quick update.

I have the CPU maxed out on its multiplier of (16) at the moment, with a bus speed of 233, with the RAM running at 1,866 with loose timings, this gives me a CPU clock speed of 3,730 with a 0.05 voltage increase to the CPU, no other voltages have been modified.

Even though we are at the beginning of a "heatwave" (compared to the torrential rain we have had for the last 4-months) the CPU has not got hot and the CPU fan has not had to run fast so far. However I have not stability tested it with Prime95 yet, I have just been using it for general purposes + Skyrim + Diablo 3, the latter only taxes the CPU to the tune of about 25%.