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Discussion Starter · #1 ·
Hey, I'm new here, so be nice :wink:

I have an AMD64 X2 4600+, on an ASUS AM2 M2V motheboard. It has 4 RAM/DIMM slots (A1,B1,A2,B2), and A1 and B1 are each occupied by a 512Mb stick of DDR 2 RAM (4-4-4-12-16-1T), and these are running in dual channel. My plan was to buy another 2x512Mb sticks similar to the ones I have at the moment, to expand my memory to 2Gb. However, I saw this: http://www.xbitlabs.com/articles/memory/display/2gb-ram.html

It clearly shows that for the most part, 4x512 is SLOWER than 2x512, which I find odd. But apparently its something to do with the 1T command rate dropping to 2T, and dual channel being disabled. So basically, what do you suggest I do? I havent got a huge budget, so buying 2x1Gb sticks of DDR2 may be difficult, but I dont want less performance from getting another 2x512. Also, does getting another 2x512 and putting them in A2 and B2 mean that dual channel will be disabled for them all, and would the new sticks have to match the present ones, or just each other?

Thanks alot for your help :)
 

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Hi,

What is the RAM speed? You will want to make sure your RAM will have the same timings and the same speed. And put each pair in a separate channel so check the manual so make sure you do. That way, you will get dual channel. Remember, those are just benchmarks, and the real world applications are more important, especially with dual core processors.
 

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Discussion Starter · #3 ·
Its DDR2 533 4-4-4-12-16-1T. I'm guessing I could also get, say, DDR2 667 5-5-5 etc, but decrease it to 533 and 4-4-4 etc.

Would the extra RAM actually increase the speed of the system overall do you think- does the loss of speed from the 1T-2T timings become insignificant compared to the advantages of having twice the RAM?

Thanks
 

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The RAM in your system will all run at the slowest timings, so getting more DDR2 533 RAM @ T. 4-4-4-12 would not slow the timings at all. And as long as you use 2 pairs of matched dual channel pairs, then you will still have dual channel. So you will only gain speed, the RAM speed itself won't be slower. Having 2 GB of RAM is especially useful for using virtual machines like VMWare, because you can set the allowed RAM space to 1 GB. Also, if you ever run Linux in a dual boot setup or not on a virtual machine, having 2 GB will make a HUGE difference, when I upgraded to 2 GB of RAM (see "My System") from 1 GB, all my programs in Kubuntu opened in half the time as before, and gaming also improved.
 

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The problem of which you speak was concerning the onboard CPU memory controller. That problem was "fixed" with the E6 stepping on the toledo and above cores

the venice and windsor cores suffered from the 4 stick memory limitation and not being able to run the memory at full bandwidth and 1T timings


its really a matter of what your ram is capable of now that you have the newer E6 stepping
 

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Discussion Starter · #8 ·
How can I tell whether I have this E6 stepping? I'm sure I heard problems concerning this with other AM2 X2 processors, but I may be wrong.
 

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this whole 1t to 2t thing doesnt appy to am2 and ddr2, as ddr2 runs at 2t by default, 1t is extremely aggressive for it. as for the e6 revision, which applied to s939 processors as am2 is revision f, it helped sometimes but it didnt completely erase the need for 2t timings, biggest problem it solved was having to downclock 4 sticks to 400 to 333.
 

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Floyd is correct :pray: forgot for a second that AM2 uses DDR2 but NOT exclusively there are boards that used both ddr2 or ddr memory

I was never sussessful at achieving 1T timings with stability on the asus board, as I understand it; only DFI lanparty did ?
 

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Yes there's boards that can run both, quite correct.

CL 1/1.5T are usually available on high end ASUS, Biostar or DFI boards. Can be found on others too and certainly the BIOS can be modded to present this option with stability such as the Biostar P965 Deluxe BIOS for "some" Biostar mobo I don't recall the name of. :rolleyes:

In terms of speed, the memory controller is very important as is the RAS to CAS timing mainly because when memory bursts occur adjacent cells are read not needing CAS and when rows are interchanged (quite often) its the RAS thats is needed. When its columns then the CAS becomes of prime importance.

RAM performance does increase by timings definitely.

Here's in 2002 with some DDR timing benchmarks:
http://tomshardware.co.uk/2002/05/07/perfect_timing/page4.html
 

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Discussion Starter · #12 ·
Oh, thats strange then. Because I'm pretty sure I'm at 1T with DDR2 (4-4-4-12-16-1T). I have an ASUS board, but not a high end one.
 

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thats weird. the board wouldnt really have much to do with it though, its the memory controller on the cpu. i know for a fact that its pretty much impossible to run 1t on intels, maybe amd is a little more forgiving... thats cool i guess, doesnt make a huge difference, but still.
 

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Oh, thats strange then. Because I'm pretty sure I'm at 1T with DDR2 (4-4-4-12-16-1T). I have an ASUS board, but not a high end one.
Memory timings are in this notation: tCL-tRCD-tRP-tRAS
Yours are 4-4-4-12
Your CAS is 4
Thats what affects performance along with the RAM capability and Memory controller. The fastest latencies are 1.0, 1.5, 2.0 and the slower are the CL 3 and above.
 

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And remember, the speed will always still be a factor. So DDR400 with timings of 3-3-3-8 will be slower than DDR2 800 RAM with timings of 4-4-4-12 even though the CL is higher. This is because the timings have been reduced on the DDR2 800 modules.
 

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Discussion Starter · #16 ·
The CLs (the first number) arent the problem, its the command rate, which I think comes at the end. Some say you cant run 4 sticks at 1T.
 

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Yes though the chipset-to-memory delay (CRD) is fastest at 0T<1T<2T where the standard is 1T and 2T found everywhere. Some motherboards will run at 1T perfectly even with 4 modules but most will be too unstable to, like running at 0T.

If you put 4 modules in, it will most likely default to 2T and their is a big difference indeed. Just look at this old comparison of timings: here
 

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your best bet is to google search for overclockers who had tweaked your "exact" same set-up

motherboard, ram config, & cpu

you will find you need to adjust the hypertransport multiplier, the ram volts, ram settings, fsb & multiplier

its a combination of all the above & then test it with a stability testing program like Prime
 
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