RAM: lower CAS or more MB? Which is better?

lung

Senior member
Apr 17, 2002
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I was just wondering, which is generally better for overall performance on a P4 2.4C system?

1GB of PC3200 ram (CAS2.5 or 3) or 512MB of PC3500 ram (CAS2)? Both would be with using two sticks to make the total so as to use them in dual channel mode.

Thanks.
 

sao123

Lifer
May 27, 2002
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1 GB of PC3200 CAS2 (Usually Kingston HyperX or Corsair Gold or something) would be your best option unless your gonna overclock it.

PC 3500 is only good if your gonna overclock it, and is only available in CAS 3.

Read this article from toms hardware...
http://www.tomshardware.com/motherboard/20030812/ddr500-01.html
small quote included...
We conducted a variety of tests in which we operated DDR400 memory at ideal timings (2-2-6, CL2.0) before repeating the readings at conservative timings (3-3-6, CL2.5). While the variance is measurable, they were voided if the system-clock speed was raised only slightly. A mere 3 MHz of extra FSB speed is enough to outperform the optimized system with run-of-the-mill timings...

but the article goes on to basically explains that CAS 2 is meaningless on a system with greater than PC3500 - 4000 (FSB 434 - 500) because CAS 2 is no longer attainable in stable configurations. 3-4-4-8 is currently the only supported timing for dual channel ram PC 3500 & PC 4000.
 

savx

Member
Mar 24, 2003
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Well... it depends on your use!

There should be no doubt whether you want to swap w/ disk (ie 512 vs 1024) or squeeze out a little more throughput (ie CAS 2 vs 2.5).

If your PC use require more than 512 MB, than it's a no brainer... go w/ 1024

If all your applications you run on average, consumes < 512, than go w/ faster RAM for higher memory bandwidth (better performance).

So, you need to look at average memory consumption (as well as peak) and then make a decision.
 

bjc112

Lifer
Dec 23, 2000
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PC 3500 is only good if your gonna overclock it, and is only available in CAS 3.

Totally not true. Maybe in PC 4000, and even then the timings are getting better.

Me personally i would go with a Gig as the difference between Cas 2 and 2.5 is minimal at best...

If you get some Buffalo you should be able to grab 512 for about $99 and run it @ PC 3500 speeds...

Reguardless, you can run a 250 bus on the 5:4 divider.. ( While only pushing your ram @ 200mhz )

Go for the gig.
 

Big Lar

Diamond Member
Oct 16, 1999
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Its a bunch of hogwash that you can't get better performance with pc3500, especially running it at 2226.
 

sao123

Lifer
May 27, 2002
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Its a bunch of hogwash that you can't get better performance with pc3500, especially running it at 2226.


Unless your gonna push you momory to 434mhz, there is no benefit of PC3500 no matter what timing you use.
Thats like buying a P4 3.4Ghz and underclocking it to 3.2Ghz.

Like i said
PC 3200 will run at 22261 @ 400 Mhz .... Kingston HyperX MFR Suggested price for 1x 512MB Stick $140
PC 3500 is rated for (I apologize for my earlier inaccuracy) 23371 @ 434 Mhz ...Kingston HyperX MFR Suggested price for 1x 512MB Stick $155.

Unless your gonna run it to its full potential...Y Waste your money?
 

Jeff7181

Lifer
Aug 21, 2002
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Most of the PC3500 you see that says it's CAS 3 is CAS 2 or CAS 2.5 that's overclocked and has to be run at CAS 3 to be stable... yet you pay a premium for the "PC3500" label.

So... if you are looking for PC3500... if you find "CAS 3 PC3500" it's probably nothing more than overclocked PC3200 RAM... and you'd be better off buying your own PC3200 RAM, saving some money, and overclocking it yourself.
 

xenos500

Senior member
Jul 22, 2003
354
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Maximum clock speed and CAS latencies are related. Say you have PC3200 CAS2 (200mhzDDR) and want to overclock it to PC3500 CAS2(233mhzDDR) You would be stressing the ram. If you moved it to CAS2.5 or 3, It would be good to go. Same is true is reverse, if you have PC3500 but arent overclocking it (IE your FSB isnt running at 233) you can lower the CAS to 2.5 or 3. Some motherboards support CAS1, you might be able to get away with that if you have PC3500 and are running it in a P4 system with 133 or 100mhz ram speed.

Im pretty sure you dont need a gig of ram yet, I'd get the high quality 512 and then add more HQ 512 later when you find you need that much.

"If you dont know if you need that much, you dont need that much"
My new philosophy ^
 

Jeff7181

Lifer
Aug 21, 2002
18,368
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If you want to know how much you need... Ctrl+Alt+Del then start up your most demanding game... play it for a while, then return to the desktop and check what it says your Peak Commit Charge is. If you don't have at least that much RAM, the computer is forced to use virtual memory for some stuff, which will decrease performance.
 

FPSguy

Golden Member
Oct 26, 2001
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Do as Jeff7181 says. If you don't need the extra RAM, get the higher speed RAM. The PC3200 will take your P4 2.4C to 3 GHz on a 5:4 ratio. Maybe it will go higher with relaxed timings but you never know how much you can get out of it. The PC3500 should take your P4 2.4C to 3.25 GHz. Maybe it will go higher than that but again you would be overclocking the memory and you never know how much more you will get out of it. Unless your applications truly need more than 512MB of RAM, the system with the faster processor is going to be faster.
 

sykopath79

Senior member
Nov 2, 2000
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Originally posted by: sao123
PC 3500 is only good if your gonna overclock it, and is only available in CAS 3.

Wrong... Mushkin Level 2 PC3500 is rated for CAS 2. Read your AnandTech a little closer ;)
 

sao123

Lifer
May 27, 2002
12,653
205
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Originally posted by: sykopath79
Originally posted by: sao123
PC 3500 is only good if your gonna overclock it, and is only available in CAS 3.

Wrong... Mushkin Level 2 PC3500 is rated for CAS 2. Read your AnandTech a little closer ;)

Plz read all my posts thoroughly before flaming me, proving what a dumbass you really are.

Like i said
PC 3200 will run at 22261 @ 400 Mhz .... Kingston HyperX MFR Suggested price for 1x 512MB Stick $140
PC 3500 is rated for (I apologize for my earlier inaccuracy) 23371 @ 434 Mhz ...Kingston HyperX MFR Suggested price for 1x 512MB Stick $155.

 

lung

Senior member
Apr 17, 2002
236
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Originally posted by: Jeff7181
If you want to know how much you need... Ctrl+Alt+Del then start up your most demanding game... play it for a while, then return to the desktop and check what it says your Peak Commit Charge is. If you don't have at least that much RAM, the computer is forced to use virtual memory for some stuff, which will decrease performance.
Hmm.. Well, I have dual monitors so I was able to watch it real-time. Only when playing BF1942 did it ever go over 512MB and only by about 20MB. Everything else only bumped it up to about 475MB. So it looks like for now, I will go for the higher speed, 512MB route. Maybe once HL2 hits the stores I will grab another 512MB. Thanks for the help guys.