Upgrade not straightforward!

[Jake_UK]

Hi folks,

I just got two new sticks of RAM, they are https://www.scan.co.uk/products/8gb-...9-9-24-xmp-15v and are identical to the original pair.

I expected this to be the easiest of all upgrades but am left scratching my head! Neither Linux or Windows recognises the full 16GB, both only see 8GB. The BIOS at boot also only sees 8GB.

Thinking the new sticks had a problem (they are 2nd hand) I booted with only the new pair in there and did so without problem.

So I checked mobo compatibility: good up to 32GB.

Ran Memtest+ next and saw that all 4 x 4GB sticks are shown in 'Memory SPD Informations' but only 8GB seems to be properly recognised and being tested.

I'm not sure what to do next, other than flash the BIOS but that seems a long shot and a PITA... any ideas??

[Jonj1611]

Check the new pair in every ram slot. Could be the slot itself that is faulty.

What motherboard is it

[kalniel]

BIOS only seeing 8gb is a problem. This sometimes occurs if you have a bent pin in the CPU socket due to over tightening. Try checking the RAM slots first, but if that fails to solve it then you might need to reseat the CPU carefully, taking the opportunity to get a good few phone shots of the socket while you're at it..

[AGTDenton]

What is the make and model of the Motherboard you have?
Or PC if it's prebuilt.

[zaphod159]

Had a similar issue when I was installing RAM couple years ago on my at the time 7 year old system. My issue was that the RAM did not sit properly into the slots, even though they seemed to fit. After fiddling around with it and literally pushing it in, it worked and I didn't have any issues with it after that. So make sure the new ones are actually sitting in tightly!

[ik9000]

Hi folks,

I just got two new sticks of RAM, they are https://www.scan.co.uk/products/8gb-...9-9-24-xmp-15v and are identical to the original pair.

I expected this to be the easiest of all upgrades but am left scratching my head! Neither Linux or Windows recognises the full 16GB, both only see 8GB. The BIOS at boot also only sees 8GB.

Thinking the new sticks had a problem (they are 2nd hand) I booted with only the new pair in there and did so without problem.

So I checked mobo compatibility: good up to 32GB.

Ran Memtest+ next and saw that all 4 x 4GB sticks are shown in 'Memory SPD Informations' but only 8GB seems to be properly recognised and being tested.

I'm not sure what to do next, other than flash the BIOS but that seems a long shot and a PITA... any ideas??

as others have said what mobo and what cpu? I had a mare with my board and ram a year or so ago. Could not get it to play nice. Thought the ram was duff. Got new ram same issue. Turns out for the volume and speed of RAM i was trying to use the cheap i3 processsor fell over. swapped cpu for i7 (same socket, same mobo, same RAM) and everything then worked. Turns out that generation of CPU had a gimped memory controller on the i3 chips so 2GB modules were fine, 4GB were not. Rather than just recognise a lesser amount it crapped out with errors on booting. The i7 with its better controller not only handled 4GB chips (it's s1156 so rather old now) but could run them all the way to 2200MHz just fine.

The mobo manual said the 4GB chips were fine and supported - and they were. What it didn't say was only with an i5 or i7. Weeks of misery. I still have the spare RAM sticks gathering dust if anyone wants some DDR3 2133 let me know!

[Jake_UK]

It's a Shuttle SZ77RG with an i5 3570K (running at stock).

Attached is a screenshot of Memtest showing that all DIMM slots are recognised (4 x 4GB) but that the memory is still shown as just 8GB... this is what puzzles me!



I've tried rearranging the sticks in the DIMMs and giving them a bit of a further push down after they click into place: All configurations work other than using only the red DIMMs only - these are the secondaries for the two data bus so I presume that is 'right' that doesn't work.

Looking through the BIOS release notes there isn't anything that leaps out in terms of the updates that indicate they'd help here.

[Jonj1611]

I would reset the bios or could be a bent pin in the CPU socket as already mentioned

[ik9000]

If you've checked it's seated properly can you go into configuration and turn off XMP? Crazy i know, but the one thing I can see is two different xmp banks which maybe, just maybe messing things up.

Check dual channel is set to active.
manually set the DRAM clock speed, multiplier etc.
Manually set memory voltage to 1.5V etc etc.

any joy?

Can you screenshot the configuration menu too?

Hang on, have you checked the mobo specified RAM slot pairings? shouldn't slots 01 and 23 be the pairs? try swapping 1 and 2 around.

[Xlucine]

I've tried rearranging the sticks in the DIMMs and giving them a bit of a further push down after they click into place: All configurations work other than using only the red DIMMs only - these are the secondaries for the two data bus so I presume that is 'right' that doesn't work.

Err, that doesn't sound right to me - I've never heard of RAM slots not working unless others are populated

[ik9000]

I've heard of it somewhere where the RAM chips had been changed. The original used 8 chips of x capacity, the newer refresh used 4 chips of 2x. Same serial number etc, but the internal addressing was apparently different enough to cause problems.

I think it's interesting the two XMP profiles and different in the BIOS. I'd start by turning it off and setting manually to see if that gets you out of the woods. If not contact corsair and find out if there have been any changes under the hood.

[Jonj1611]

Also try a live Linux cd/usb and see if that reports the same mem size

[Jake_UK]

Yesterday I flashed the BIOS and that had no effect on the RAM. I also manually increased the voltage to the DIMMs and that didn't do anything either.

I need to take the cooler off the CPU to remove it from the mobo so I'll need to get some more thermal paste before I do that so I can put it back on again afterwards. I'll put up some screenshots of the BIOs options I have tonight in the hope that I don't need to all that!

[ik9000]

don't up the ram voltage. manually set it to 1.5v. you're not trying to run it beyond default.

[Jake_UK]

Err, that doesn't sound right to me - I've never heard of RAM slots not working unless others are populated

The four slots on the mobo are colour-coded; two yellow, two red. The yellow are used if only two sticks installed. So I guess the dual bus runs through each of the yellow slots which then connect to the red ones.

If you've checked it's seated properly can you go into configuration and turn off XMP? Crazy i know, but the one thing I can see is two different xmp banks which maybe, just maybe messing things up.

Check dual channel is set to active.
manually set the DRAM clock speed, multiplier etc.
Manually set memory voltage to 1.5V etc etc.

any joy?

Can you screenshot the configuration menu too?

Here are the menu settings I have:



Here's the XMP submenu - it was always set to 'Automatic' but 'Manual' gave these options to me (using these defaults but under manual mode didn't affect anything):



Here's the Voltages, etc. submenu - this is where I tested manually increasing the power to the DIMMs:



Let me know if these give anyone any ideas, I only know what about half of it means! Thanks.

I'll also download a Linux LiveCD overnight to try that suggestion...

[ik9000]

ok, it's not recognising the XMP profile. You have the RAM modules installed correctly so far as i can tell from that mobo description.

because it can't load the XMP settings it is seemingly doing nothing in the BIOS.

set memory profiles to manual
change DIMM voltage to manual and 1.5V
change DRAM frequency to manual and set the speed. Your bios should display the options with the memory clock mutiplier applied to the cpu baseclock. NB it will be half what you think it shuold be (due to DDR) so for 1600 you're looking for 800Mhz. If not you may need to adjust the memory clock multiplier and memory multiplier to a different ratio depending on what the cpu baseclock is set to (usually either 100 or 133 MHz).

get the spec sheets for both types of RAM and check all the values are set right. to obtain these you'll need the full serial numbers for both sets of RAM from the stickers on the units themselves. don't use anything else. You;ll be surprised that seemingly the same RAM can have a subtly different tRandomDigit tucked away that you need to massage. There are plenty of guides online to explain all the different t (timing) ratios. It's all relative to the memory clock speed and how data is processed along the RAM module.

Are you familiar with clock speed and multipliers? Basically everything runs in reference to a set speed - the base clock . The CPU speed is bclk * multiplier (usually approx 40x-50x) so say 100MHz x 40 = 4000MHz approx 4GHz (not exactly due to 1024 blah blah blah)

Similarly the RAM is scaled from the same clock. The memory clock is derived by a multiple of the blck, and the RAM speed by that mem clock x RAM multiplier usually 8-12 or thereabouts.

So you need to work from what speed is the CPU bclk, and what RAM speed do I utlimately want (800MHz). Scale the mem clock ratio and mem multiplier to achieve that target. Set it in stone. Done. It's only an issue when you play with overclocking the CPU but you've confirmed you want to keep it at stock. For ivy bridge K series you can change the cpu overclock by changing the CPU multiplier but NOT the bclk (which is usually fixed) so actually manually setting the RAM shouldn't matter as much anyway. It was harder in the old days where you had to fiddle with bclk too, as that changes all the voltages and chaos if you weren't careful.