is cas2 33% faster than cas3

[gogeeta13]

elementy school math would say cas2 should be 33% faster than cas3 right?

 

[gogeeta13]

nobody has any imput?

 

[rominl]

nop, it's just about 2-3% faster for CAS2

 

[gogeeta13]

really, can you explain the texhnicals

 

[Moohooya]

Nope I can't, but it is something like

2-3-3-3-3
vs
3-3-3-3-3

Basically memory now accesses multiple rows at once, typically 4. The column is only one delay, the row is another.

So we are talking 15 cycles vs 14 cycles (assuming it takes 3 cycles to pump a row back.) I've no clue how many cycles it really is. Different memories have differnt timming. Burts DRAM shaved a cycle of the row, I believe at the expense of the column. I forget what SDRAM does.

Perhaps CAS2 is 7-8% faster than CAS3, but then there are two levels of caching. So rominl's 3-4% sounds good to me

Moohoo

 

[Kingofcomputer]

Even it's really 5% faster than cas3 in memory performance, you overall computer performance won't be increased by 5%, could be just 0.5% or even less. The law is when you increase one component's speed, the whole computer won't be improved by that amount.

 

[gogeeta13]

so is there really any point in buying cas2 ram(specifically pc133 sdram)

 

[birddog]

THe CAS 2 ram is generally better at reaching higher clock speeds. Most CAS 2 PC133 cah hit 150+ CAS3.

 

[rominl]

hmm, that's interesting. i can't say for sure what's the true reason, but what Moohooya suggests sound very reasonable. i guess it's just like why when you go from PC100 to PC133, you are not getting 33% gain as well...

maybe what happens is when you access memory, sometimes it takes one less cycle, but then it doesn't mean you access memory every cycle? just my thought

 

[rominl]

yup, if you just intend to run at 133, cas2 probably doesn't worth coz' they are usually just hand-picked ram with a higher price tag. but if you want to push them to run at higher fab like 140+, probably you need them.

 

[gogeeta13]

i'm getting a tbird 1 gig and plan to run it as high as i can, so should i ge cas2 pc133 and while i'mn at it, should i get a 266 or 200 tbird

 

[Demon-Xanth]

I've found going from 3-3-3 to 2-2-2 noticably increases speed, even on my Ali5 based system

 

[Kingofcomputer]

Unless the price is same or within few bucks, I'd buy the cheaper one.
right now crucial 256M cas3 and cas2 price difference is just $4, I'd definitely buy the cas2 stuff.
but a new star just shows up - Corsair pc150 cas2 for just $99, hard to decide whether to pay $10 more for sure pc150 cas2.

 

[rominl]

if 266 athlon is not much more than 200, get 266, more flexible, trust me.

and if you want to bump the fsb to 145+, i'd say get some pc133 cas2, you have a much better chance.

 

[gogeeta13]

hmm, while i'm here, what motherboard would you guy s recomend. i want to get another maxtor 30gig and run raid.

 

[Demon-Xanth]

I have an Epox 8KTA3 sporting an 850@1GHz that I'm happy with. So far it's kicking the @#^% out of my previous P5A+500K6-2 setup so hard (in both speed and stability) that I'm giving the P5A to a friend that helped with an engine swap.

 

[rominl]

iwill kk266-r?