Overclock makes Ram unusable?

Landoflemon

Hi, just have a strange problem I can't quite work out,

I used to have 4GB of Corsair Dominator Ram and overclocked my i7 860 from 2.8 to 4.2Ghz successfully with no problems, I was rendering animations at the time. Since then I now have 8GB of the same Ram, but when I overclock to 4.2 it tells me that I have 8GB installed, but only 4GB is usable. Why is this so?

I only noticed it when I began seeing a strange trend in superpimod benchmark results, of lower performance when overclocked.

sink

Are you by chance running a 32-bit OS? as they can only support a max of 4GB of RAM.

Landoflemon

Sorry, I should have made it clearer, I've got 64 bit windows 7. When its at the standard clock speed (2.8Ghz) all 8GB's or Ram is usable, it's only when it's overclocked that it becomes limited to 4GB.

gerryk

How are you doing the OC? Multiplier or FSB?

Landoflemon

I'm not hugely experienced in this sort of thing but as far as I can remember, I think I left the multiplier at x21 and set the base frequency to 200MHz, then set voltages at values I can't remember but I read them from a guide. My ram is rated at 1600MHz, but by default its running at 1333MHz, so I just change that manually to 1600MHz, and increase the voltage going to the ram to 1.65V (this is what is rated on the sticks anyway).

deceit

Landoflemon wrote: »

I'm not hugely experienced in this sort of thing but as far as I can remember, I think I left the multiplier at x21 and set the base frequency to 200MHz, then set voltages at values I can't remember but I read them from a guide. My ram is rated at 1600MHz, but by default its running at 1333MHz, so I just change that manually to 1600MHz, and increase the voltage going to the ram to 1.65V (this is what is rated on the sticks anyway).

When you overclock the speed of the ram will increase also and you have too change settings too alter that so when its at its highest overclock it can still run fine, maybe your first 4 where good sticks that could handle the extra oc and the newer ones couldnt? If thats the case could try a few extra volts and see if that helps in anyway, but usually 4 sticks makes it harder too overclock in general.

Landoflemon

Thanks for the reply, yeah I had changed the ratio to 2:8 which meant that with that particular overclock the ram stayed at 1600MHz, that's what I think I can remember at least anyway. Over the next few days once my final college exams are finished I'll have another go at it and post back if I get anything to work.

niall_f

To high multiplier may be the reason also to high frequency.

Dublin_Gunner

Landoflemon wrote: »

Thanks for the reply, yeah I had changed the ratio to 2:8 which meant that with that particular overclock the ram stayed at 1600MHz, that's what I think I can remember at least anyway. Over the next few days once my final college exams are finished I'll have another go at it and post back if I get anything to work.

If you clock your ram back to 1333 does it then recognise all 8GB??

Some motherboards / memory controllers will only allow all slots populated up to a certain ram speed, like 1333Mhz. You'll need to keep your ram on whatever divider keeps them at 1333 or lower I'd say.

For it to suddenly not address 4GB of ram would not suggest a ram problem, but a memory controller problem.

Ironside Rocks

you could try something for me go in the start menu in windows and in the run option enter msconfig , go to boot then advanced options and see what the max mem in there is that being set wrong will tell you in boot 8 but win will report what ever this is . had this problem when i clocked my m4A88TD-M evo mobo / 1055t from 2.8 - 3.6 in feb .

Landoflemon

Thanks for the replies, In the next day or 2 I should be able to reply again with further detail, I'm just back home after a few weeks and the grass needs a serious cutting. Also have a new 120GB SSD to install too.

Landoflemon

I think I may have somewhat solved the over clock problem. I did a mild over clock to 3.37Ghz and increased the voltage going to the Ram just above the recommended of 1.65 to 1.67 and in my system properties it said that all 8GB of Ram were usable so that's a bit better anyway.

However..... Since then the SSD booting the OS started working really slowly during boot time, and now it won't boot at all and I get a "AHCI Port1 Device Error" on startup. I'm now rather concerned about this and couldn't care less about the over clock anymore!!

Next time I'll just get a Dell :-/

It is worrying me now that in September I'm starting a Masters in Computer Engineering, but I just seem to spend the majority of my time messing up computers!

Landoflemon

Ok, I've now fixed the problem with the SSD. It wouldn't even recognise it in the BIOS anymore, just reconnected the SATA cable to a different port on the motherboard and was able to see the drive again, reinstalled windows and then added on my 2 other drives in RAID 1. I'm not going to bother messing around with overclocking with this machine I think, I'm just happy it's working in its stock setup!

Thanks for the help and suggestions in solving my overclock problem. I'll wait until I've something easier to overclock like a 2600K.

Dempsey

Regarding your SATA problem, sounds like you didnt lock or set the AGP ratio to 'Auto' in the BIOS setting for the overclock.

Dublin_Gunner

Dempsey wrote: »

Regarding your SATA problem, sounds like you didnt lock or set the AGP ratio to 'Auto' in the BIOS setting for the overclock.

Please find me a P55 / X58 board with an AGP slot....

The SATA issue is most likely caused by having the main system bus OC'd too far, and the chipset / SATA controller has become unstable.

A little more voltage there may help stabilise things.

Dempsey

Dublin_Gunner wrote: »

Please find me a P55 / X58 board with an AGP slot....

The SATA issue is most likely caused by having the main system bus OC'd too far, and the chipset / SATA controller has become unstable.

A little more voltage there may help stabilise things.

I dont have a P55 / X58 manual to call out exactly what it is named in its BIOS, probably called 'PCI-E Lock'. It might be renamed on newer motherboards but the principle of the function is still the same. This shouldnt have to be explained to overclockers tbh.