RDRAM NooB: What is the diff between PC-600, PC-800, PC-1066 etc....

[Herkulese]

I know what the DDR-Ram numbers mean, PC-2700 runes at 166fsb, PC-3200 runes at 200fsb etc, but I am a complete noob to RDRAM.

What is the brakedown of PC-600, 800, 1066, 1200 etc.....

If I was going to run a 1.7 Celeron (P-4 based) with 256mb, which should I use?

What is best and cheapest, and where should I buy it from?

Do you have to fill all slots?

Newegg shows 184 pin (16 bit) and 232 pin (32 bit) RIMMS, how do you know which one you need?

 

[AndyHui]

It's a little out of date, but the AnandTech FAQ: What is RDRAM? should address your questions nicely.

Don't ever consider anything slower than PC800 RDRAM.

All slots must be filled, either with a RIMM or a C-RIMM (blank).

 

[Mr.IncrediblyBored]

The PR nomenclature for RDRAM designates the "effective" clock frequency of the RAM modules. RDRAM transmits data on both the rise and fall of the clock cycle (just like DDR-RAM - twice per clock), so a PC-600 module runs at 300mhz actual, and 600mhz effective.

PC600 - 300mhz
PC800 - 400mhz
PC1066 - 533mhz
PC1200 - 600mhz

 

[Herkulese]

Thanks for the link and other info.

How do these numbers apply to PC fsb speeds?
For example, you need PC-2700 DDR Ram to run at 166fsb.

What is this brakedown with RDRam, or is the speed set some other way?

If you want a total 256mb, and your mobo has (4) slots, is it better to run (2) 128's and (2) C-Rims, or (1) 256 and (3) C-Rims?

 

[dullard]

Originally posted by: Herkulese
Thanks for the link and other info.

How do these numbers apply to PC fsb speeds?
For example, you need PC-2700 DDR Ram to run at 166fsb.

What is this brakedown with RDRam, or is the speed set some other way?

If you want a total 256mb, and your mobo has (4) slots, is it better to run (2) 128's and (2) C-Rims, or (1) 256 and (3) C-Rims?

The previous poster has all the info you need about P4 fsb (RDRAM naming is quite straightforward while DDR you have to memorize or get out a calculator):

PC600 - 300mhz (600 MHz effective hence the name PC600)
PC800 - 400mhz (800 MHz effective)
PC1066 - 533mhz (1066 MHz effective)
PC1200 - 600mhz (1200 MHz effective)

Thus a 400 MHz fsb P4 matches the best with PC800 since both run at 400 MHz. A 533 MHz fsb P4 matches the best with PC1066. Of course you can use faster or slower memory, but in general I'd recommend against it.

RDRAM for the most part is installed in pairs. Thus you need either 4x64 MB and 0 crimms or 2*128 MB and 2 crimms.

 

[dexvx]

Memory speed is arbitrary to FSB. PC2700 DDR SDRam operates at 166FSB because a lot of users choose to run at a 1:1 ratio to the FSB.

RDRam boards usually have 3X or 4X multipliers. Meaning if you run at 100FSB and use 4X, you would get 400Mhz or PC800. At 133Mhz, 3X is 400Mhz and 4X is 533Mhz (PC1066).

Another note, I doubt anyone would recommend coupling a p4-Celeron with a RDRam system. RDRam is meant for high performance.

 

[Herkulese]

Another note, I doubt anyone would recommend coupling a p4-Celeron with a RDRam system. RDRam is meant for high performance.

TRUE, but some of the boards are very inexpensive and the ram is also not that expensive.

For example:
ComgGeeks has an D850GBA for $20.00 + $9.00 shipping ($29.00)
GoogleGear has 128mb PC-800 for $41.00 each shipped (2 for $82.00)
NewEgg has Celeron 1.7 P4 (Retail w/HS & Fan) for ($53.00 shipped)

Thats $164.00, not bad for this combo, for a woman who will never OC, nor play any games. She does medical transcription, office apps, quick books, and e-mail.

 

[Wiktor]

Still, I think a P4 would benefit you much more than any Celeron, so why not get a 2.0GHz P4 ? That and a 400MHz FSB board (like the D850GBA) and 256 PC800 RDRAM makes a nice system.

 

[Herkulese]

"so why not get a 2.0GHz P4 "

Approx. $100.00 is why.
________________________________

Your point is valid, but money talks.

 

[dexvx]

Originally posted by: Herkulese
"so why not get a 2.0GHz P4 "

Approx. $100.00 is why.
________________________________

Your point is valid, but money talks.

So why get an RDRam system? Those are meant to be paired with high performance machines. They are more expensive than DDR SDRam, and you're only going to save on the cost of the motherboard.

 

[Sunner]

Originally posted by: Herkulese
"so why not get a 2.0GHz P4 "

Approx. $100.00 is why.
________________________________

Your point is valid, but money talks.

If you're after price/performance, AMD is the way to go really.
A lower end AXP with DDR is hard to beat for a good low end system.

Like Devx said, RDRAM is meant for systems where performance is the most important factor, something a Celeron most certainly isn't.
It's kinda the opposite of getting a P4 3.06 GHz and putting it in a system with 128 MB of PC-133 SDRAM(well no, not that bad, but you get the point).

 

[Herkulese]

"So why get an RDRam system? Those are meant to be paired with high performance machines. They are more expensive than DDR SDRam, and you're only going to save on the cost of the motherboard."

I found a D850GB RDRam Socket 423 P4 MoBo at CompGeegs that was only $20.00, and I had also found some inexpensive RDRam, and that is why I needed to know the difference in the speeds, as that makes a defference in the price.

I have opted to go with an AMD based system for this on though, because, as has been stated several times in this thread, you can get batter quality and higher speed SDRam for a lot less money that RDRam and the MoBo price is truly a wash.