memory : benefits of higher speed or lower CAS?

[Garulfo]

Hi,

I am about to buy a new computer. I am going for either 2gb or 4gb, all 1gb sticks.

I have been looking on Newegg, reading review, and reading some tests on anandtech.com as well. I learnt about the timing values (kinda) and especially the CAS one.

Now, it seems that the only 1gb sticks with a good CAS value (2, as mentionned on anandtech.com) are DDR400 PC3200 sticks. The OCZ platinum or Corsair XMS ones, for instance.

Now I see that there are plenty of other types of memory with much higher speeds/frequency. Up to DDR 900 I think. There is even DDR2 ram.

The higher speeds don't even seem to be more expensive on newegg, but their CAS values go up.

I want to go for a good brand, but have no idea if DDR2 is faster than DDR and if I should aim for a DDR900 with a CAS of 4 or a DDR400 with a CAS of 2.

Btw, the motherboard would be either an Asus A8N SLI premium or an MSI K8N neo4 SLI.

Thanks for any input!

 

[acole1]

DDR2 is only for Pentiums whereas DDR is primarily for AMD. If you want to OC get something with a moderate CAS (2.5-3) in a good brand (OCZ, Giel, some Corsair) and nice fast speeds (pc3200+).

Here is a good article if you dont know much about Memory Timings. It will get you started atleast.

(feel free to correct me if someone has a better opinion on the ram advice.)

 

[Garulfo]

Ok, my computer will be AMD based... So, if I had to choose between say :


OCZ Platinum Series 1GB DDR400 (PC3200), Cas Lat:2 (2-3-2-5)

Or a stick of OCZ (or another good brand) DDR600 with a CAS of 4

which one should I choose?

PS: I cannot seem to find any 1GB sticks faster than DDR400. They seem to only offer 512MB sticks. If that is really the case and DDR400 is the faster 1GB sticks I can find then it will make my choice easier. I want to be able to go up to 4GB fairly soon.

 

[acole1]

1GB sticks usualy are not very good for overclocking. only recently have their been any developments in that market so 512 will have to work for that.

i would suggest something like this. it would probably be all you really need unless your going to hard core OC with water cooling and all.

if you want to go with something cheaper. here are some more OCZ options. just take your pick... and make sure it is compatible with your motherboard.



if you are looking for something without overclocking just pick a PC3200 with the lowest CAS values possible... (2 preferably ... 2.5 is ok). this will give you an efficient and stable system. with the best bang for your buck.

this might be something to look at.

this might be a bit high CAS but it would work too.

right now there is absolutly no advantage to anything over 2GB. (as far as i know BF2 is the only game that even makes any use of 2GB). and when you jump into the 1GB stick range you really reduce your efficiency. so someone with 4x512 will kill your 4x1024 even though you have 2x the amount of ram. my suggestion would be to get 4x512.

 

[Garulfo]

I read the same thing, about the 512 sticks being much better than the 1gb ones. Until they recently release the low latency 1gb though, one being the OCZ platinum, another the crucial XMS. It was an article here on anandtech.com. That's when I decided to go for 1gb sticks.

 

[chocoruacal]

This is pretty simple: buy the fastest 2GB (2x1GB) kit you can afford. There are several kits that offer decent 2-3-2-x timings. I wouldn't get hund up on the DDR speed at this point. Why? Because on Athlon 64 systems you can use a divider to keep the memory at or below its rated speed without any performance hit.

For example: I run my HTT at 300 and a divider puts my RAM at 200mhz. If I benchmark using the divider above and below, the results are the same.

 

[Budarow]

Originally posted by: chocoruacal
This is pretty simple: buy the fastest 2GB (2x1GB) kit you can afford. There are several kits that offer decent 2-3-2-x timings. I wouldn't get hund up on the DDR speed at this point. Why? Because on Athlon 64 systems you can use a divider to keep the memory at or below its rated speed without any performance hit.

For example: I run my HTT at 300 and a divider puts my RAM at 200mhz. If I benchmark using the divider above and below, the results are the same.

I've always heard speed wins out over tighter timings (e.g., 500MHz RAM with CAS 3 would perform better than 425MHz RAM at CAS 2)? So wouldn't it make sense to buy the fastest speed memory (even with looser timings) and use a divider to overclock the CPU (i.e., NO OC'ing of the faster RAM)?

The fast RAM (e.g., 500MHz 2GB kits) I've looked at all seem to have loose timings.

 

[edmundoab]

If you are overclocking then its a good idea to get over PC3200 as you can keep your memory at 1:1 Ratio

 

[fireontheway]

Link

 

[hurtstotalktoyou]

Originally posted by: Garulfo
Ok, my computer will be AMD based... So, if I had to choose between say :


OCZ Platinum Series 1GB DDR400 (PC3200), Cas Lat:2 (2-3-2-5)

Or a stick of OCZ (or another good brand) DDR600 with a CAS of 4

which one should I choose?

PS: I cannot seem to find any 1GB sticks faster than DDR400. They seem to only offer 512MB sticks. If that is really the case and DDR400 is the faster 1GB sticks I can find then it will make my choice easier. I want to be able to go up to 4GB fairly soon.

Memory latency has a minimal impact in system performance. Considering that you can get 2GB name-brand memory for $167, it doesn't make much sense to spend $87 extra for a ~2% speed boost. The money would be better spent on a bigger (or second) hard disk, nicer case or better CPU.

Also, many motherboards that claim to support 4GB are actually limited to 3GB. Make sure to read the fine print in the manual of whatever boards you're considering.

 

[skdevnath]

guys what do you think about this memory
Twinx2048-3200c2pt

and

Twinx2048-3200c2

both has 2-3-3-6

I don't what is the different between them one has pt at the end of it's name.