Wrong speed

CaseyChaos

CaseyChaos

CaseyChaos

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I have 2x2gb of corsair value 667mhz pc5300 in a shuttle sg33g5, no matter what i set the bios to cpu-z says that im running the ram at 4:5 ratio, i have my fsb at 334mhz to give me 3ghz on my q6600, which cpu-z says the mem is running at 418mhz, ive had one bsod in the past 2months and one lock up lately while playing need for speed undercover, is cpu-z wrong? the lowest i can set the mem to in the bios is 667mhz which gives me 836mhz, currently ive set it to 'by spd' which is still giving me the 836mhz, I can't seem to remove the 4:5 ratio so if cpu-z is right then i'm stuck
 
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is there no option for 1:1 ? that would give you 333/334 MHz. Make sure nothing in the memory setting is set to auto. Set the VDIMM and timings to what they should be
 
You are confusing the bus speed of the system with the effective speed of the memory, which is doubled since it's double data rate.

So, if your bus speed is 334Mhz and have a ratio of 4/5 then the effective speed of your memory is 835Mhz. This is well above the stated 667MHz of the PC2-5400, so it no wonder you have been getting BSODs:

(334 /4 * 5) * 2 = 835Mhz

you 334MHz overclock on a 1:1 would be 668Mhz which is fine

Give my DDR2 guide a read through
 
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im not confused, maybe i worded it wrong, i kno that my fsb of 334 is doubled to get my ram rating of 667 which is what im trying to achieve, everything is fine apart from i can't remove the 4:5 ratio, there is no option in bios of 1:1 if i could set that I'd be fine. i was just lookin around the new cpu-z see if anything was new when i came across the problem.

CPU-ZRAM.jpg
 
Admiral Huddy said:
You are confusing the bus speed of the system with the effective speed of the memory, which is doubled since it's double data rate.

So, if your bus speed is 334Mhz and have a ratio of 4/5 then the effective speed of your memory is 835Mhz. This is well above the stated 667MHz of the PC2-5400, so it no wonder you have been getting BSODs:

(334 /4 * 5) * 2 = 835Mhz

you 334MHz overclock on a 1:1 would be 668Mhz which is fine

Give my DDR2 guide a read through
Click to expand...


The OP is correct m8.

CPU-Z should state 1:1 even though it will show 800mhz (DDR Speed) PC6400 as 400mhz (Real Clock).
 
yeah sure, been over the bios very carefully, no mem ratio option at all

CPU-Z.jpg


found this on a different forum using google

With the Corsair XMS2 RAM used, "By SPD" and 667 both correspond to a 4:5 divider, while the 800 setting corresponds to a 2:3 divider. Needless to say, the lack of precise settings, and particularly a 1:1 ratio, is limiting if trying to push the performance as high as possible
Click to expand...

does this mean I'm going to have to go out and get some new ram, 800mhz corsair xms2 is about £40 for 4gb so i guess it won't break the bank, it'll still be running at 836mhz but at least the 800mhz should be able to handle it better than 667mhz
 
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Most BIOS manufacturers don't actually use the ratio any more. Instead, they quote in available memory frequencies pre-calculated so the maths is done for you. All you have to do is select the frequency nearest your stated RAM regardless of the FSB.

To access this, change your RAM setting from AUTO to Manual. It should give you an option to select the DRAM Frequency. By changing this, you are effectively setting the ratio.

For example, if you change your FSB Frequency to 376MHz

then you can select 750Mhz as the DRAM frequency (1:1 Synchronous) but here are higher options available which make the memory work Asynchronously.


That said, you would be better off with higher frequency RAM since you are over clocking.
 
there are only 3 options for dram frequency by spd, 667mhz and 800mhz. both by spd and 667mhz make the ram work at 4:5 ratio and give me 836mhz and the 800mhz will run at 2:3 ratio and run the ram at 1002mhz. ill just have to buy some new ram and let it run at 836mhz
 
You are missing something or you have a weird Bios.

The SPD is not even used by many peeps esp OC'ers.

SPD is only Jedec's naff for setting Timings and Voltage, you need to set the Memory to Auto to follow the FSB 1:1 or manually pick a speed after setting the FSB (normally a drop down menu) of a few Speeds/Dividers inc 1:1.
 
helmutcheese said:
You are missing something or you have a weird Bios.

The SPD is not even used by many peeps esp OC'ers.

SPD is only Jedec's naff for setting Timings and Voltage, you need to set the Memory to Auto to follow the FSB 1:1 or manually pick a speed after setting the FSB (normally a drop down menu) of a few Speeds/Dividers inc 1:1.
Click to expand...

if i set it to auto, it still sets it to 4:5 ratio, there are not settings for the ratio at all, just the by spd, 667mhz and 800mhz, ive said that before.

the motherboard is the one that comes with the shuttle sg33g5 whichever that is
 
I have just read this about your system:

"There is only a handful of options, though. For example, the BIOS lacks control over the Core 2 multiplier, and memory speed options are limited to 667 and 800MHz."

I know this doesn't help. However, Make sure that Speedsteep, C1E and Auto Overclock are disabled.

Also look for any BIOS updates, as if all the above are disabled, there is clearly a problem.
 
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