CAS Help

topgun06 · 19 Apr 2006 at 13:33

Hi there,

Basically I’ve decided to upgrade from my Dual channel 1GB Geil PC3200 to a 2GB Dual channel kit. I’ve been looking through the memory here at OC and at other online stores and I can’t seem to find memory that suits my needs for anything less than around £150.

But what I’m asking is what difference (if any) would I see between CAS2 and a CAS3 memory in loading times, and in games such as Battlefield 2? I’ve seen many memory sets with CAS3 for my budget.

Ideally I am after a 2GB CAS2 Dual channel PC4000 or better for around £150. Should I be expecting to pay more for this type of memory?

Any help will be appreciated, thanks.

atheus · 19 Apr 2006 at 15:43

topgun06 said:
Hi there,
But what I’m asking is what difference (if any) would I see between CAS2 and a CAS3 memory in loading times, and in games such as Battlefield 2?

You won't see any difference in loading times - these are HDD limited. You would see some difference in memory bandwidth benchmarks and maybe gain a few FPS in your games.

Dunky · 19 Apr 2006 at 15:47

Difference in FPS being very little, you might see a couple of FPS (from 65-70 FPS for example) but I doubt it would be of any significance. If you're going to overclock, have a look at the forums and go for memory which is known to overclock well (such as OCZ). Otherwise, go for value-type memory and save your money.

The difference between CAS 2 and CAS 3 is highly exaggerated, and it's not worth spending more money just for sake of getting CAS 2.

4T5 · 19 Apr 2006 at 15:48

Hi Topgun and welcome to the boards.
Post the rest of your spec for a better Ram match up.
You Will see a difference in loading times with BF2 as i did when i went from 1gig to 2gig. Much less pagefiling on larger maps and smoother running on higher settings.

topgun06 · 19 Apr 2006 at 17:53

Thanks for the help so far. Im glad the CAS won't make that much of a difference.

malc30 said:
Post the rest of your spec for a better Ram match up.

Spec:

Asus A8N-SLi Premium nForce4
GeIL 1GB PC3200 Dual Channel
Athlon 64 X2 4400+ @ 2.43Ghz
2 x XFX 7800GT Extreme 256MB in SLI

Steve_h · 19 Apr 2006 at 20:12

Hi hope you don't mind me posting here,but some of my questions have just been answered.
I have gone from the Geil value pc3200 1gb and upgraded to the Geil 2gb "this week only" ram.
Just like topgun06 I was also wondering about the CAS issue but that was cleared up as above

so what about the timings as the are different as well,now I'm a complete noob on this subject so go easy on my here

Are these timings ok/bad /indifferent?
and are there any recommendations you guys could give me?I'm not into overclocking but would like to make sure that for the sake of a few bios settings I am getting the best from my new ram.
My system is a 3200 Barton on a nforce2 board running in dual channel.
cheers

Usher · 19 Apr 2006 at 20:17

Apparently cas2 is pointless on AMD64 anyway & should be set at 2.5 according to numerous write ups on the net

Minstadave · 19 Apr 2006 at 22:49

Usher said:
Apparently cas2 is pointless on AMD64 anyway & should be set at 2.5 according to numerous write ups on the net

What? Thats blatantly nonsense, are you thinking of CAS 1.5 not actually working and CAS2 being just as good?

Minstadave · 19 Apr 2006 at 22:51

Steve_h said:
Hi hope you don't mind me posting here,but some of my questions have just been answered.
I have gone from the Geil value pc3200 1gb and upgraded to the Geil 2gb "this week only" ram.
Just like topgun06 I was also wondering about the CAS issue but that was cleared up as above
so what about the timings as the are different as well,now I'm a complete noob on this subject so go easy on my here Are these timings ok/bad /indifferent?
and are there any recommendations you guys could give me?I'm not into overclocking but would like to make sure that for the sake of a few bios settings I am getting the best from my new ram.
My system is a 3200 Barton on a nforce2 board running in dual channel.
cheers

Your geil should work nicely with the following settings:

CAS 2.5
tRP 3
tRCD 3
tRAS 11

Vdimm - 2.7 or 2.8 (if 2.7 is unstable use 2.8)

That should get the best out of your 2Gb Geil Value

Usher · 20 Apr 2006 at 09:32

Minstadave said:
What? Thats blatantly nonsense, are you thinking of CAS 1.5 not actually working and CAS2 being just as good?

No, the advice given just about everywhere for AMD64 suggests setting Cas at 2.5

Dunky · 20 Apr 2006 at 10:11

Usher said:
No, the advice given just about everywhere for AMD64 suggests setting Cas at 2.5

I think this comes from Corsair memory where certain CAS2 modules say they'll run at CAS 2 for Intel boards and CAS 2.5 on AMD boards. However these modules 9 times outta 10 will run fine at CAS 2 on AMD boards. CAS 1.5 is a bit of a fake since according to the AMD tech docs, it doesn't actually exist.

topgun06 · 20 Apr 2006 at 12:27

Ok, so am I right in thinking that this is probably the best buy for me, if i can find it any cheaper elsewhere?

OCZ 2GB (2 x 1GB) PC4000 Dual Channel Gold GX XTC Series EL-DDR CAS3 (OCZ5002048ELGEGXT-K) (MY-060-OC)
Price: £149.95 (£176.19 Including VAT at 17.5%)

Defcon5 · 20 Apr 2006 at 13:21

Dunky said:
I think this comes from Corsair memory where certain CAS2 modules say they'll run at CAS 2 for Intel boards and CAS 2.5 on AMD boards. However these modules 9 times outta 10 will run fine at CAS 2 on AMD boards. CAS 1.5 is a bit of a fake since according to the AMD tech docs, it doesn't actually exist.

And i think the mem controller throws a hissy fit and defaults to Cas3 doesnt it?

Dunky · 20 Apr 2006 at 17:18

Defcon5 said:
And i think the mem controller throws a hissy fit and defaults to Cas3 doesnt it?

Corsair modules usually have SPD at 3-x-x-x (CAS 3) and you have to manual change it - at least this was the case for certain modules (the AMD CAS 2.5 ones anyway) as I remember plenty of posts of people asking "My CAS2 Corsair is running at CAS 3...I was ripped off, etc etc..."

Steve_h · 20 Apr 2006 at 20:26

Minstadave said:
Your geil should work nicely with the following settings:

CAS 2.5
tRP 3
tRCD 3
tRAS 11

Vdimm - 2.7 or 2.8 (if 2.7 is unstable use 2.8)

That should get the best out of your 2Gb Geil Value

thanks for the info Minstadave,just one thing why does the tRAS need to go up to 11? At present the default is 8,isn't lower better :confused:

I did warn you I was a noob at this lol

brightside_ · 20 Apr 2006 at 20:48

2.5-3-3-6 for Geil Value, at 2.7V or 2.8V

Dunky · 20 Apr 2006 at 21:05

Steve_h said:
thanks for the info Minstadave,just one thing why does the tRAS need to go up to 11? At present the default is 8,isn't lower better
I did warn you I was a noob at this lol

Ball park figure for tRAS is the add the two middle values in x-x-x-x together and add one (or two). I.e for 2-2-2-x it should 2-2-2-5 or 2-2-2-6. The only exception is AXP and nF2 boards, in which case 11 was recommended (dunno why).

People have done benchmarks on each timing part in x-x-x-x format and tRAS (the last number) had no/neglible difference. The second number (RCD I think) has the greatest difference between timings (hence why most 2GB CAS2 modules are 2-3-2-6 since RCD of 2 puts the memory (controller) under a bit of strain especially for 1GB modules).

Steve_h · 21 Apr 2006 at 19:04

Ok guys,cheers for the info,i'll give it ago.

Street · 22 Apr 2006 at 12:54

topgun06 said:
Ok, so am I right in thinking that this is probably the best buy for me, if i can find it any cheaper elsewhere?

OCZ 2GB (2 x 1GB) PC4000 Dual Channel Gold GX XTC Series EL-DDR CAS3 (OCZ5002048ELGEGXT-K) (MY-060-OC)
Price: £149.95 (£176.19 Including VAT at 17.5%)

Why don't you go for a PC3200 set with tighter timings and run the RAM on a divider if needs be? Would be better than getting a PC4000 set IMO especially if you aren't using super high HTTs on your chip.