Frequently asked questions about memory and storage:

[TestSpecimen]

Just a quick question, which is more desirable when buying memory; high frequencies or low latencies? An example would be DDR2 800 at 4-4-4-12 vs. DDR2 1000 at 5-5-5-15. Does the increased MHz make up for the higher latency, or is it better to have the slightly slower RAM with the lower latency?

 

[BlueAcolyte]

Those two examples would be about equal, but I think Intel chips favor bandwidth (speed) over timings. Not that it really makes a difference at this point.

 

[danielhcn]

Hi all.My system running WinXp Pro(32 bits).Currently,i have Corsair 4x1Gb of DDR2 800.I palnning to upgrade my ram to 4x2Gb DDR2 1066.Will it improve my rigs performance if i still running WinXp 32 bits???

 

[sticks435]

Originally posted by: danielhcn
Hi all.My system running WinXp Pro(32 bits).Currently,i have Corsair 4x1Gb of DDR2 800.I palnning to upgrade my ram to 4x2Gb DDR2 1066.Will it improve my rigs performance if i still running WinXp 32 bits???

You'll get more memory bandwidth moving from 800 to 1066, but will be limited by only being able to use 3.25 gigs like posted above, and with 8 gigs, I would strongly recommend moving to Vista x64.

 

[rebecca1286]

wow i learned a more here thanks a lot friends but i have dought about DIVIDING BY 4
is this necessary for all latest processors ......
can some one explain it
thanks in advance

 

[rebecca1286]

wow i learned a more here thanks a lot friends but i have dought about DIVIDING BY 4
is this necessary for all latest processors ......
can some one explain it
thanks in advance

 

[BlueAcolyte]

Originally posted by: rebecca1286
wow i learned a more here thanks a lot friends but i have dought about DIVIDING BY 4
is this necessary for all latest processors ......
can some one explain it
thanks in advance

If you mean the Intel FSB,
1) The number is bigger, so that's some marketing right there.
2) The Intel CPUs can transfer 4 pieces of data at once, so Intel feels that they can get away with #1.

 

[myocardia]

Originally posted by: shangshang
Actually it doesn't.

PC electronics are discrete, so you can't have 333.333...-infinity because it's not discrete.

Yeah, it's probably just 333.333333333. Not like it makes much difference either way, though.

Originally posted by: minmaster
thanks. could you explain why it's divide by 4? is that the case for all cpu's?

It's because Intel's FSB is "quad-pumped", as they call it. That means that it is able to transfer data 4x per clock cycle. In other words, it gives you the performance you would get with 4x the clockspeed, without it having to actually run 4x as fast.

 

[survivor1940]

don't know if this is the right forum for this
I was thinking of getting the AsRock G43 Twins full HD LGA 775 Mobo with (2) modules of 2x1gb of ddr2 800 pc2 6400 mem. with 4-4-4-12 timings.but need to know if there will be a problem with using the Intel E5200 cpu?

 

[BlueAcolyte]

Sure, don't see why not. An E5200, even overclocked, shouldn't stress the motherboard OR the RAM.

Don't worry about it, it should work fine.

 

[survivor1940]

Is there anything I should consider concerning the voltage on the memory. I see some of them show 1.9 or 2.1

 

[BlueAcolyte]

Generally you would like RAM with lower voltage, but higher is ok. RAM that gets 2.2v or more needs more cooling. Lower voltage is cooler. (also the case for other components) However RAM needs higher voltage to hit those tight timings and high speeds.

 

[survivor1940]

as you can tell I am not to computer savvy that is the reason for the questions.I will look for something with 4-4-4-12 and cl of 4 not sure about the cl 5 and 1.8 or 1.9 v I just don't know enough if I have to start changing voltage I will not be overclocking or doing any gaming.

 

[Onund]

Originally posted by: myocardia

Originally posted by: shangshang
Actually it doesn't.

PC electronics are discrete, so you can't have 333.333...-infinity because it's not discrete.

Yeah, it's probably just 333.333333333. Not like it makes much difference either way, though.

Ah man, you shouldn't have given up so easily. shangshang was wrong, the PLLs are analog blocks. The main clock synthesizer obtains it's reference from a 14.31818MHz crystal. For 333MHz clock output, the VCO output frequency is set to 1000MHz then divided by 3 to get 333.333333...MHz as you said.

The actual frequency really depends on the M,N and O divider values and the PLL might not be running at precisely 1000MHz, depending on the PPM spec, requirements for overclocking and design of the clock chip. Also, if spread spectrum is enabled then the frequency will be changing by 0.5% or 1% (usually) but this is typically used in notebook design for EMI reduction and wouldn't be the case on desktops.

So, technically the CPU clock is probably not running at 333.333333...MHz, but in theory, that is the target.

So, in summary, your PC is discrete based on a reference clock. That reference clock uses analog circuitry and can generate any arbitrary frequency within the normal operating region of the PLL.

 

[BlueAcolyte]

Originally posted by: Onund

Originally posted by: myocardia

Originally posted by: shangshang
Actually it doesn't.

PC electronics are discrete, so you can't have 333.333...-infinity because it's not discrete.

Yeah, it's probably just 333.333333333. Not like it makes much difference either way, though.

Ah man, you shouldn't have given up so easily. shangshang was wrong, the PLLs are analog blocks. The main clock synthesizer obtains it's reference from a 14.31818MHz crystal. For 333MHz clock output, the VCO output frequency is set to 1000MHz then divided by 3 to get 333.333333...MHz as you said.

The actual frequency really depends on the M,N and O divider values and the PLL might not be running at precisely 1000MHz, depending on the PPM spec, requirements for overclocking and design of the clock chip. Also, if spread spectrum is enabled then the frequency will be changing by 0.5% or 1% (usually) but this is typically used in notebook design for EMI reduction and wouldn't be the case on desktops.

So, technically the CPU clock is probably not running at 333.333333...MHz, but in theory, that is the target.

So, in summary, your PC is discrete based on a reference clock. That reference clock uses analog circuitry and can generate any arbitrary frequency within the normal operating region of the PLL.

AAAAAAAAAAAGHHHH!!! It huuuuuurrtssss!!! :brokenheart:

Anyway, survivor, if your needs are that basic, I would recommend modules that use 1.8v. There isn't a big performance difference between 5-5-5-18 and 4-4-4-12. But modules with the default voltage 1.8v will be cooler and probably less troublesome under harsh conditions.

 

[survivor1940]

just checked the asrock website and they don't show any info for memory support. I would like to install the Corsair 4Gb (2x2gb) ddr2 800 (pc2-6400) but not sure if it will default to 1.8V.I know my 32 bit system will only rec a little more than three at this time but if I want to change to 64 bit in the future I will have the needed memory.

 

[BlueAcolyte]

The Corsair will most likely work, it's just that motherboard companies can't test every single combination. Anyway, even if it doesn't default (which it always should) you can go into BIOS and change it. Don't worry, enjoy more memory.

 

[survivor1940]

Why does it show 1.8> 1.9 v on some of the modules? If the motherboard asks for 1.8 should I not look for modules that show only 1.8v or will it default to 1.8 like I mentioned I really am not sure about changing anything in the bios.Is there any way someone can list memory I should consider for the Asrock MoBo?

 

[BlueAcolyte]

The motherboard will default to 1.8v but can be set up to ridiculously high voltages like 2.5v... Don't worry so much...

 

[murphy55d]

How much, if any difference am I going to see going from an IDE hard drive to a SATA one? I never got around to upgrading my hard drive, I was considering picking up a Seagate 7200.11 500GB off NewEgg. Not going to bother though if i won't see much of an improvement. I'll save my money and get something else.

Just light gaming, internet usage on this PC. Nothing intensive.

 

[BlueAcolyte]

Not too much. Run a benchmark such as HD Tune on your current hard drive and compare it to the results of SATA drives.

 

[chadomaly]

thanks for this post BlueAcolyte. It's been about 5 years since i've done a system overhaul and the FSB speeds were messing with my head. That cleared it up as to which I need. Have yourself a virtual beer on me

 

[BlueAcolyte]

:beer::beer::beer::beer::beer::beer::beer::beer::beer::beer::beer::beer: Hic!

 

[GLeeM]

Thanks for the info, BlueAcolyte

With more people buying i7 and the necessary DDR3 could you explain the differences we need to take into account.
How the different speeds effect overclocking?
How to calculate what speed is needed?
Is there a ram volt limit for i7? How could high ram volt hurt CPU?

On my old computer I overclocked the ram (FSB) to speed up the CPU (I think), what is happening when OCing i7? Does the ram have to be OCed to OC the CPU? (Maybe some of this doesn't belong here) Things have changed that I don't understand

Thanks for any clarification you/anyone can add.

 

[BlueAcolyte]

Ok, I don't know a lot about i7. Here is what I do know:

DDR3 transfers data 2x as fast as DDR2 at a given frequency (so ddr2-1066 runs at 533mhz while ddr3-1066 runs at 266mhz)
You will still be limited by RAM speed while overclocking, of course.

RAM volts are not recommended to go over 1.6v on i7 CPUs since not only does ddr3 use less energy, but the memory controller is now INSIDE the CPU.

On your old computer, you overclocked the FSB, which sped up both RAM and CPU.
On i7, you up the bclock (base clock?) which is similar to FSB. When overclocking i7, you are limited by the fact that bclock also raises other values. You do not have to OC RAM to OC a CPU as long as the RAM:FSB ratio is properly set.

(example: Core 2 Duo E8400 at 3.6ghz [400fsb] with DDR2-800 is a 20% overclock, but setting the RAM to a 1:1 ratio will have it run at normal speed)

Sorry if this is confusing.