Newbie help: Value Ram good for overclocking?

[UzairH]

Sorry for posting this I know its probably been discussed before, but I'm buying a new system tomorrow and there seem to be conflicting views of people... The gurus here as well as people who have OC'ed using such RAM please help.

The deal is this: The only availble RAM here in Pakistan is Kingston Value Ram CL3 DDR400. I'll get 512 x 2 for $120. Also the only s939 PCI-E mobo is the MSI nForce4 SLI board for $230 (yikes) or hopefully MSI nForce4 Ultra (non SLI). I am building this system to be a bit future-proof, OC it and I think it'll last a couple of years.

Now will the value ram allow me to OC to 2.4 GHz or even 2.6 GHz? Again sorry, I have got a little idea of OCing from the excellent A64 OC guide here but this is something I can't answer. Those of you who have used the MSI nForce4 mobos, and value ram, please comment. I suppose if I really can't OC to at least A64 2.4 GHz it makes little since to buy this A64 system, I can ge a P4 530 one for about $100 less.

Sorry again for n00b question... help is appreciated

 

[NetDevil]

Cas3 isn`t very good. You could get Corsair Value Select cas2.5 for 100$ or so from newegg. Anyway i`d recomend you for you to search for some cas2.5 ram even if it isn`t a brand name like kingston. But with a memory divider you should be able to clock your processor at 2.5ghz or so.

 

[edmundoab]

zipzoomfly has the cas 2.5 1GB kit for 93.90 free 2 day air ship last I checked.

 

[UzairH]

Yeah people but I'm here in Pakistan where most people think a Celeron is good value (like most non-geeks think Dell is good in the USA, os I've heard). So my _only_ option is this CL3 RAM. Will it make it impossible for me to reach 2.6GHz or 2.4GHz on my soon-to-be A64 3000+?

 

[SrGuapo]

Originally posted by: UzairH
The only availble RAM here in Pakistan is Kingston Value Ram CL3 DDR400.

Last I checked newegg doesn't deliver to pakistan...


You won't be able to OC that RAM much (maybe 210-220). However, you could just set a memory divider and still OC the CPU. This won't be a very large performance hit.

Edit: If you can get the 30 cheaper and if you have a good mobo/HSF, you shuld get good performance out of that. However, that would require DDR2 RAM, which may or may not be available in pakistan at reasonable prices...

 

[Acanthus]

KVR tops out at around 220mhz (440 ddr) in my experience (10 512MB modules)

DDRII isnt available in the US at reasonable prices and you most certainly dont need DDRII for a celeron rig, just get a 915P chipset motherboard.

 

[UzairH]

Uhm Acanthus I'm getting a whole new system... so I'll put in a new processor as well. Since I have zero experience of overclocking, could you gentle (cough) geeks & gurus guide me - I think even though this RAM may not go high I could set a low mem divider to keep it about 400 MHz; but does lowering the divider (increasing this number actaually, since it's a divider, but this sounds more natural) ... does lowering the divider to keep RAM freq low negatively effect other performance areas? If not this seems like an easy to way to get great OC even with value ram.

 

[UzairH]

And if I do get the P4 530 I'll put it onto an MSI 915G combo board - the only non-intel board available here. The combo board has both DDR and DDR2 slots. Using DDR 400 on the 915 board won't affect performance I hope... help required please!

 

[Acanthus]

It will not. It seems you have the right idea you can run the memory on a divider rather than keeping it at a 1:1 ratio.

The performance penalty for the divider is negligible as long as you dont run some insane divider like 1:2 on 400fsb (DDR200) as long as you keep it near or slightly above DDR400 the KVR should be fine.

 

[UzairH]

Thanks Acanthus for the assurance. But I am a bit confused now looking at Zebo's Official 939 Memory Matrix thread... according to his testing value ram is noticeably slower in Far Cry in an overclocked setup. I would think that simply running the divider to set the mem freq to its nominal rating wouldn't harm it. I mean, you say that running a mem divider of 1:2 on 400fsb for getting DDR200... wouldn't the divider set the mem to original DDR 400 MHz? Under normal frequencies, divider 1:1 with 200MHz FSB gives DDR 400 right? So why doesn't 1:2 at 400FSB again give DDR400? I must be missing something here, being an utter n00b! ;-/

 

[3chordcharlie]

You only have a few dividers to choose from, and there's a good chance your highest processor OC will come with a ram speed of below 200/400mhz. You might end up better off lowering the OC slightly in order to get the ram back up near stock speeds; only benchmarking will let you be sure though. Good overclocking ram gives you more flexibility this way, but you don't have that available; I wouldn't worry about it.

If you end up with ram at 380mhz or something like that, then yes, your memory benchmarks will be slower than in a non-OC'd system; but the overall system may well still be faster than stock.

 

[UzairH]

OK this is confusing me a lot, and I mean a lot, when you say you are changing the RAMdivider what it means is you are changing the RAM freq, say from 200 to 166. Now is it correct to say that when this RAM freq is lowered, because the FSB is increased at the same time, the actual working RAM freq remains the same nominal 400MHz? I mean in this case the lower RAM freq should not affect the RAM bandwidth, correct?

Somebody help me please!

 

[UzairH]

Right I think the following applies:

Actual RAM freq (or bandwidth) = [(lowered) RAM freq in BIOS] * [FSB]

So say I have CL3 DDR 400, I set the FSB to 266.7 to get 266.7*9 = 2400 on the CPU. In order to maintain the RAM at 400MHz all I have to do is set the RAM freq to 150MHz instead of 200MHz? In this case the bandwidth doesn't get reduced?

Man I'm confused

 

[Acanthus]

yes, you can use a 3:4 ratio and that would work.

 

[UzairH]

Another thing, Anandtech reviews keep saying that A64 systems are much happier with memory command rate of 1T than 2T. Damn Kingston has no documentation on their value ram. Could those of you who are knowledgable about this please tell me if the Kingston Value Ram CL3 supports1T? And if overclocked with the ram freq lowered and fsb raised, will the 1T setting have to be changed to 2T?

 

[3chordcharlie]

Originally posted by: UzairH
Another thing, Anandtech reviews keep saying that A64 systems are much happier with memory command rate of 1T than 2T. Damn Kingston has no documentation on their value ram. Could those of you who are knowledgable about this please tell me if the Kingston Value Ram CL3 supports1T? And if overclocked with the ram freq lowered and fsb raised, will the 1T setting have to be changed to 2T?

AFAIK all ddr ram runs it's rated speed at 1T; anything PC3200 should do so, for sure.

 

[UzairH]

OK someone settle this once and all for me please: When the RAM frequency is lowered to compensate for the higher FSB, does the ACTUAL RAM bandwidth go down because of the low "divider" or ram freq? Or does the bandwidth remain the same, being calculated as the product of FSB and divider?

 

[richardrds]

Uzairh,

You will be fine with that value ram. I just recently upgraded to 1G ram with tighter timings, but my initial A64 S939 config was a 3000+ Winchester with 512M 3-3-3-8-1T Value ram. I overclosked the CPU from 1.8Ghz to 2.5Ghz (278Mhz HTT) and ran a 2/3 RAm divider, so my mem was only running at 179 Mhz. But quess what, this is fine with the A64 archetecture, It is not like P4's or AMD XP's that are memory bandwidth hungry. Read Zebo's excellant Sticky on this subject, you will only be taking a 2-5% performane hit for running that Value ram with the divider. For a 2-5% perormance hit it is not worth paying 2-3 times as much on memory, use the value ram and run the divider .


http://forums.anandtech.com/messageview...atid=28&threadid=1475190&enterthread=y

 

[3chordcharlie]

Originally posted by: UzairH
OK someone settle this once and all for me please: When the RAM frequency is lowered to compensate for the higher FSB, does the ACTUAL RAM bandwidth go down because of the low "divider" or ram freq? Or does the bandwidth remain the same, being calculated as the product of FSB and divider?

The bandwidth is a product of the FSB and the divider. So if your ram is actually running at 200mhz, you should get the same bandwidth (i.e. 250 w/ 5:4 divider is the same as 200 with 1:1 divider). On P4 and K7 systems, using dividers tended to reduce performance, because of synchronization issues; I don't know if that's the case with A64, but I imagine it would be; from what I've read here, it sounds like the performance hit isn't very big for running dividers with A64 though.

 

[UzairH]

Thanks richardrds Another very n00bish question though... since I have no experience with OC or *real* mobos (see sig). How is the divider set in the BIOS? Is is seperate from where you specify the RAM freq? is it an actual ratio represented as 2/3, 4/5, etc in the BIOS? And do ALL the nForce4 based mobos support the dividers? As I said, I am getting an MSI nForce4 Ultra or SLI mobo. Do these support dividers over a large enough range?

And once again: When the RAM frequency is lowered to compensate for the higher FSB, does the ACTUAL RAM bandwidth go down because of the low "divider" or ram freq? Or does the bandwidth remain the same, being calculated as the product of FSB and divider?

 

[UzairH]

Originally posted by: 3chordcharlie

Originally posted by: UzairH
OK someone settle this once and all for me please: When the RAM frequency is lowered to compensate for the higher FSB, does the ACTUAL RAM bandwidth go down because of the low "divider" or ram freq? Or does the bandwidth remain the same, being calculated as the product of FSB and divider?

The bandwidth is a product of the FSB and the divider. So if your ram is actually running at 200mhz, you should get the same bandwidth (i.e. 250 w/ 5:4 divider is the same as 200 with 1:1 divider). On P4 and K7 systems, using dividers tended to reduce performance, because of synchronization issues; I don't know if that's the case with A64, but I imagine it would be; from what I've read here, it sounds like the performance hit isn't very big for running dividers with A64 though.

Whoops sorry I re-asked this question above - hadn't refreshed thr page before re-asking.
So what your saying is that running dividers does not reduce bandwidth over normal clocked 200MHz * 2 or DDR400 ram?

 

[Quentin]

I have some experience with Kingston Value Ram CL3 DDR400. Eight of nine 512MB modules I tested individually in the systems below ran at 228-235 MHz. One module only ran at 205. Timings were set at 2.5-3-3-11, optimal for nForce2 boards vDimm was stock 2.6v. All four systems run at 10.5x230 if vDimm is 2.7. (Trats' modded BIOSes were used to increase the A7N8X FSB.)

Hopefully you have similar luck!

 

[3chordcharlie]

Originally posted by: UzairH

Originally posted by: 3chordcharlie

Originally posted by: UzairH
OK someone settle this once and all for me please: When the RAM frequency is lowered to compensate for the higher FSB, does the ACTUAL RAM bandwidth go down because of the low "divider" or ram freq? Or does the bandwidth remain the same, being calculated as the product of FSB and divider?

The bandwidth is a product of the FSB and the divider. So if your ram is actually running at 200mhz, you should get the same bandwidth (i.e. 250 w/ 5:4 divider is the same as 200 with 1:1 divider). On P4 and K7 systems, using dividers tended to reduce performance, because of synchronization issues; I don't know if that's the case with A64, but I imagine it would be; from what I've read here, it sounds like the performance hit isn't very big for running dividers with A64 though.

Whoops sorry I re-asked this question above - hadn't refreshed thr page before re-asking.
So what your saying is that running dividers does not reduce bandwidth over normal clocked 200MHz * 2 or DDR400 ram?

If the ram is running at the same speed (200/400) then bandwidth should be pretty much the same (you might have a small loss due to asynchronus ram and htt speeds). If you run a divider that causes the actual ram speed to be under 200/400, then you would have lower bandwidth.

 

[Techno Pride]

funny.

people here have been able to overclock Kingston valueram to at least 240mhz at loose timings.

those are hynix BT or DT-D43 sticks

 

[Acanthus]

Originally posted by: Techno Pride
funny.

people here have been able to overclock Kingston valueram to at least 240mhz at loose timings.

those are hynix BT or DT-D43 sticks

They start at loose timings to begin with, the 10 modules i tested couldnt do CAS2.5 on I865 or I875.