Question Memory Not Right

[ToolPunkXS]

This guy has an old computer with a AMD Phenom II X4 945 CPU and a Gigabyte GA-970A-D3 MoBo. Google says the CPU can run up to DDR3 1333 and the MoBo says up to 1800.

The PC has x2 4GB DDR3 1333 but in CPUZ it shows the RAM at only 1066mhz. When I try to set the RAM from AUTO to 1333 in the BIOS, the PC blue screens on boot. What's going on here?

Bonus question, he has x2 2GB 1600mhz will he gain anything by putting that in there or would it just confuse things more?

 

[williamjeremiah]

Time will tell.
I sure as hell don't remember. Have Fun !

 

[Aeacus]

and the MoBo says up to 1800.

There is no 1800 MT/s DDR3 speeds. What there are, are 1866 MT/s.

When I try to set the RAM from AUTO to 1333 in the BIOS, the PC blue screens on boot. What's going on here?

Then it means, the RAM frequency on that speeds isn't stable.

Just because MoBo supports up to 1866 MT/s DDR3, doesn't mean that EVERY DDR3 RAM, that is 1866 MT/s will work. RAM has to operate at JEDEC standard, which for DDR3, starts from 800 MT/s, then 1066, 1333 and 1600.

Dig up MoBo specs. There, on Support page, there is MoBo memory QVL list, that contains different RAM DIMMs that MoBo manufacturer has tested and confirmed to work at any given frequency.

Sure, RAM that isn't listed in memory QVL can work at it's rated speeds (e.g at 1866 or 1600) but chances of it are 50:50.

Bonus question, he has x2 2GB 1600mhz will he gain anything by putting that in there or would it just confuse things more?

Adding different frequency/timings/capacity RAM to already existing RAM can cause more instability, where entire system won't boot. Or the very least, RAM speed defaults to the slowest stable one.

Here's in-depth guide on why not to combine different RAM DIMMs (the mixed memory chapter),
link: https://forums.tomshardware.com/faq...y-ram-and-xmp-profile-configurations.3398926/

The PC has x2 4GB DDR3 1333 but in CPUZ it shows the RAM at only 1066mhz.

For DDR3, the RAM frequency doesn't matter. Especially since with higher frequency, you'll get higher latency as well, which nullifies any gains from higher frequency.

Here's a good short vid that explains it well about DDR3 RAM:

View: https://www.youtube.com/watch?v=dWgzA2C61z4

For DDR4 and DDR5, there are sweet spots for RAM frequency but this isn't relevant for your use case.

 

[Misgar]

The PC has x2 4GB DDR3 1333 but in CPUZ it shows the RAM at only 1066mhz. When I try to set the RAM from AUTO to 1333 in the BIOS, the PC blue screens on boot. What's going on here?

I still have a bunch of similar Phenom II X4 955 and 965 builds on Gigabyte boards. 1066MT/s is the default JEDEC speed for your DDR3 RAM. but you should be able to achieve a stable system with two DIMMs at 1333MT/s. Obviously something is going wrong here.

As for faster memory speeds on a Phenom, it's a case of diminishing returns. I did try 1600MT/s for a short period with much looser timings, but the sweet spot is 1333MT/s for many Phenom systems.

I'd suggest running MemTest86 on a pair of DIMMs at 1066MT/s to see if the RAM is 100% good at this frequency. The test might detect a bad stick of RAM at this speed, in which case, it will be even less stable at 1333MT/s.

If your friend is trying to run OCZ RAM at 7-7-7-20 1333MT/s and 1..65 to 1.90V (as recommended by OCZ), get rid of it. I had unexplained errors for years with OCZ DIMMs, which magically disappeared when I switched to Kingston.

Two DIMMs should be more stable at 1333MT/s than 4 DIMMs, so adding 2 x 2GB to the dodgy 2 x 4GB will probably be a bad idea. I'd try 2 x 2GB on their own at 1333MT/s and if the computer seems stable, run MemTest86 on these DIMMs. You'll only have 4GB RAM total, but it might be enough for the time being.

I run my 955/965 systems on XP, 7 and Windows 10, not 11. If you have a JMicron SATA controller, you might not find a stable driver for Windows 10.

 

[Aeacus]

I'd suggest running MemTest86 on a pair of DIMMs at 1066MT/s to see if the RAM is 100% good at this frequency. The test might detect a bad stick of RAM at this speed, in which case, it will be even less stable at 1333MT/s.

👍

Forgot to add testing with memtest86 to my reply. Did have it in mind when i typed my reply but forgot it at the end. 😒

What's going on here?

Memtest86 download: https://www.memtest86.com/

Guide how to install and use it: https://www.memtest86.com/tech_creating-window.html

1 full pass (all 15 tests) is bare minimum. 2 full passes are better while 4 full passes are considered acceptable.

Time wise, 1 full pass for 1x 8GB DIMM takes 1h. For 2x 8GB DIMMs, ~2.5h.
Since system has 2x 4GB, you can look ~1.25h per 1 full pass. Or ~5h for 4 full passes.

 

[kerberos_20]

As for faster memory speeds on a Phenom, it's a case of diminishing returns. I did try 1600MT/s for a short period with much looser timings, but the sweet spot is 1333MT/s for many Phenom systems.

phenom limits ram bandwith to 1333MHz, northbridge needs to be overclocked to increase ram bandwith, otherwise even if you clock your ram to 1866, it will still be limited to 1333mhz bandwith

as for ram overclock, if memory multiplier doesnt work (from xmp), fsb overclock should take care of it as that max stable ram clock is tied to northbridge clock

 

[Bob.B]

This guy has an old computer with a AMD Phenom II X4 945 CPU and a Gigabyte GA-970A-D3 MoBo. Google says the CPU can run up to DDR3 1333 and the MoBo says up to 1800.

The PC has x2 4GB DDR3 1333 but in CPUZ it shows the RAM at only 1066mhz. When I try to set the RAM from AUTO to 1333 in the BIOS, the PC blue screens on boot. What's going on here?

Bonus question, he has x2 2GB 1600mhz will he gain anything by putting that in there or would it just confuse things more?

Test each stick alone and see if either stick will boot and run at 1333.