RAM Selection Question

[kirik]

Howdy folks,

I've been considering a cheapie build that can play games reasonably well without breaking the bank...

I've decided on an E5200, EP45-DS3L, and a radeon 4850 so far but I am stuck on RAM selection. Obviously I fully intend to overclock the CPU. I have no idea how far I will OC as I have never tried a really serious OC.

I am unclear on which speed, brand, timings I should be selecting. Assuming that no OC will be taking place, would DDR2-800 suffice? If I am going to OC, should I go one step up and get DDR2-1066 instead? Asides from that, which brand / model tends to be easier to work with for the purpose of OC?

Thanks much!

[sswilson]

Because of the E5200s low FSB and high multiplier you'd have a hard time pushing DDR2 800 outside of range so you'd be fine with that.

[BALISTX]

Here is a kit that would you nicely. Mushkin EM PC2-6400 4GB 2X2GB DDR2-800 CL5-5-5-18 240PIN DIMM Dual Channel Memory Kit - $86.65 plus $3.99 2 day shipping.

[kirik]

Originally Posted by BALISTX

Here is a kit that would you nicely. Mushkin EM PC2-6400 4GB 2X2GB DDR2-800 CL5-5-5-18 240PIN DIMM Dual Channel Memory Kit - $86.65 plus $3.99 2 day shipping.

Thanks much! I will keep this in mind. :)

Originally Posted by sswilson

Because of the E5200s low FSB and high multiplier you'd have a hard time pushing DDR2 800 outside of range so you'd be fine with that.

So the better OC CPU would have a higher FSB but lower multiplier?

Example: I see the E8x00 cpus are generally recommended as easy to OC cpus. The E8500 has a standard clock of 3.16GHz. The FSB is listed 1333 MHz. Therefore the multiplier is 4.75 after taking into account the division by 2 for DDR ram. So this would be a better choice than the E5200 due to the fact that the multiplier is lower while the FSB is much higher, is that correct?

If this is the case, would I be better off with something that has a FSB of 1066 or 1333? Like something from the E7x00 or E8x00 series?

I do intend to OC my new computer btw, which is why I was having trouble with making a good choice for RAM.

[1Tanker]

Originally Posted by kirik

Thanks much! I will keep this in mind. :)




So the better OC CPU would have a higher FSB but lower multiplier?

Example: I see the E8x00 cpus are generally recommended as easy to OC cpus. The E8500 has a standard clock of 3.16GHz. The FSB is listed 1333 MHz. Therefore the multiplier is 4.75 after taking into account the division by 2 for DDR ram. So this would be a better choice than the E5200 due to the fact that the multiplier is lower while the FSB is much higher, is that correct?

If this is the case, would I be better off with something that has a FSB of 1066 or 1333? Like something from the E7x00 or E8x00 series?

I do intend to OC my new computer btw, which is why I was having trouble with making a good choice for RAM.

No...the multi is 9.5, you don't divide the multi by two..due to DDR RAM. A high multi can make for a good overclocker...it's less stressful on the motherboard, RAM and chipset. The E5200 has a multi of 12.5(and 200FSB), so what sswilson was referring to, is that..even with a 100% overclock(with the default multi)...not gonna happen w/o LN2, would use DDR2-800 for an (ideal) 1:1 RAM:FSB ratio. E8xxx are great overclockers.. but not because of the multi... because of the silicon/and 45nm process... as well as HK/MG. You need a decent motherboard and RAM(1066 or more)...as FSB's can get extremely high on the E8xxx Wolfdales. Just keep in mind, that the lowest FSB that you can run(with an Intel chipset-based mobo) is 1:1...therefore your RAM must be able to run at that speed, or your overclock will be limited to the RAMs highest frequency. GL

[sswilson]

Originally Posted by kirik

Thanks much! I will keep this in mind. :)




So the better OC CPU would have a higher FSB but lower multiplier?

Example: I see the E8x00 cpus are generally recommended as easy to OC cpus. The E8500 has a standard clock of 3.16GHz. The FSB is listed 1333 MHz. Therefore the multiplier is 4.75 after taking into account the division by 2 for DDR ram. So this would be a better choice than the E5200 due to the fact that the multiplier is lower while the FSB is much higher, is that correct?

If this is the case, would I be better off with something that has a FSB of 1066 or 1333? Like something from the E7x00 or E8x00 series?

I do intend to OC my new computer btw, which is why I was having trouble with making a good choice for RAM.

Not necessarily. Chips which start out with higher FSBs seem to offer better bandwidth at stock speeds, but once you overclock them, that high FSB (and lower multiplier) makes other hardware (like your motherboard and memory) work a lot harder to sustain an overclock, and the lower multiplier means that FSB must be tweaked higher for the same clockspeed OC on your CPU.

Think of it this way.... (these # are approximate)

On a CPU which has a stock FSB of 266 you need a multiplier of 9 to get a stock speed of 2.4G. A CPU with a stock FSB of 200 needs a multiplier of 12.

Where it starts to get interesting is when you bump your FSB by 50 on these two different CPUs......

The first CPU would get a boost of 9X50 for an OC of 2.85 Ghz, while the second would get a boost of 12X50 giving a final clockspeed on the CPU of 3G. Bumping your FSB by 50 is actually quite a minor OC, but plug in some of your own #s and you'll see that with higher bumps to FSB, the second chip pulls away from the first rather quickly in terms of cpu OC.

Added to this mix is the fact that components other than the CPU are also FSB limited at a certain point (they won't run above a certain FSB no matter what you try) so the first CPU not only scales slower as you raise the FSB, it's also starting at FSB 266 vice 200 so it's going to reach the component FSB Wall much quicker.

Does that make sense?

[kirik]

Originally Posted by sswilson

Not necessarily. Chips which start out with higher FSBs seem to offer better bandwidth at stock speeds, but once you overclock them, that high FSB (and lower multiplier) makes other hardware (like your motherboard and memory) work a lot harder to sustain an overclock, and the lower multiplier means that FSB must be tweaked higher for the same clockspeed OC on your CPU.

Think of it this way.... (these # are approximate)

On a CPU which has a stock FSB of 266 you need a multiplier of 9 to get a stock speed of 2.4G. A CPU with a stock FSB of 200 needs a multiplier of 12.

Where it starts to get interesting is when you bump your FSB by 50 on these two different CPUs......

The first CPU would get a boost of 9X50 for an OC of 2.85 Ghz, while the second would get a boost of 12X50 giving a final clockspeed on the CPU of 3G. Bumping your FSB by 50 is actually quite a minor OC, but plug in some of your own #s and you'll see that with higher bumps to FSB, the second chip pulls away from the first rather quickly in terms of cpu OC.

Added to this mix is the fact that components other than the CPU are also FSB limited at a certain point (they won't run above a certain FSB no matter what you try) so the first CPU not only scales slower as you raise the FSB, it's also starting at FSB 266 vice 200 so it's going to reach the component FSB Wall much quicker.

Does that make sense?

Much more sense.

I had mistakenly thought that (for example) the E8xxx series has a FSB of 1333, so I would need 1333 RAM. Now it is obvious that the bare minimum rating for those would be DDR2-667. So if I get DDR2-800 RAM I would have about 67 MHz to play with (assuming I don't hit the FSB wall).

I am sorely tempted to get an E5200 but the substantially smaller cache concerns me. Would the small cache make a big difference in terms of gaming?

[misterd]

Originally Posted by kirik

I am sorely tempted to get an E5200 but the substantially smaller cache concerns me. Would the small cache make a big difference in terms of gaming?

No the cache won't make a big difference. You should be ok with a E5200, what's the difference in price? I am covering my eyes until the CAD is back to something tolerable.

[kirik]

Originally Posted by misterd

No the cache won't make a big difference. You should be ok with a E5200, what's the difference in price? I am covering my eyes until the CAD is back to something tolerable.

E5200 is going for ~110 at canadacomputers, the E8500 is going for ~250. I figure if I save a bit on the cpu (where i can raise the performance after the purchase) I can get a better case and what not.