rkawakami wrote:Note sure why that is at the moment. The figures you cite are bandwidth numbers; how much data can be transmitted in one second. That spec can be affected by a few things.
Look carefully at the memtest86+ screens on both systems. What are on the following lines (I'm running version 4.20 at the moment; your information may be in slightly different locations):
1) First line on left under the green MEMTEST86+ <version>
After the Intel processor type, what speed (Mhz) is it running at?
I've got two different versions here. 4.20 (from an ubuntu 12.04 disk) and 4.37 (from the memtest86.com web site). Interestingly enough, version 4.20 gives more info than 4.37, including whether it's single or dual channel and the memory SPD information. (*edit: I stuck with info's as provided by 4.20.)
T520: is an i5-2520M @ 2.5Ghz.
T530: is an i5-3230M @ 2.6Ghz.
All modules are DDR3-1600. The 8G pair are identical manufacturer/part#s. The 4G pair are different manufacturers.
rkawakami wrote:
2) 6th line on left: IMC:
What's the BCLK rate?
3) 7th line on left: Settings: RAM:
What's the speed (Mhz) and is it indicating Dual Channel?
T520 with the two 4G modules: Memory: 10171MB/s, IMC as above (Intel Core i5 ...) BCLK is 99Mhz
RAM 664Mhz (DDR3-1329), CAS: 9-9-9-24, Dual Channel(!)
T520 with one 8G module: Memory: 6406MB/s, IMC as above (Intel Core i5 ...) BCLK is 99Mhz
RAM 664Mhz (DDR3-1329), CAS: 8-8-8-23, Single Channel
T520 with the two 8G modules: Memory: 10208MB/s, IMC as above (Intel Core i5 ...) BCLK is 99Mhz
RAM 664Mhz (DDR3-1329), CAS: 8-8-8-23, Dual Channel
T530 with the two 4G modules: Memory: 9070MB/s, IMC as above (Intel Core i5 ...) BCLK is 216Mhz
RAM 1729Mhz (DDR3-3450), CAS: 11-11-11-28, Dual Channel(!)
T530 with one 8G module: Memory: 9070MB/s, IMC as above (Intel Core i5 ...) BCLK is 216Mhz
RAM 1729Mhz (DDR3-3450), CAS: 9-9-9-27, Single Channel
T530 with the two 8G modules: Memory: 18140MB/s, IMC as above (Intel Core i5 ...) BCLK is 99Mhz
RAM 798Mhz (DDR3-1596), CAS: 9-9-9-27, Dual Channel
T530 Memory MB/s/T520 Memory MB/s:
Two 4G modules: 0.9
One 8G module: 1.4
Two 8G modules: 1.8
I would have thought it would be roughly 1600/1333 = 1.2, since the T530 calls for DDR-1600 and the T520 for DDR-1333.
(Notice that in my previous post, I had said that the T530 with the two 4G modules was running the memory at 16377MB/s. It seems I made an error(?could it be different if I swapped those 4G modules from one slot to the other?) In any case, the ratios are odd.)
Ok, I am now officially _tired_ of swapping memory modules!
