Where to get PC1066 RDRAM?

[BZMeRLiN]

I want to snag a P4 at 1.6 or 1.8 (Northwood) and run the little ******* at 133 FSB for perfect AGP/PCI. Does anyone know where I can get PC1066 RDRAM that can also run at 133 FSB, or should I just use PC800 and run it at 399 Mhz??

[littlerichie]

dual channel rambus operates at 800 mhz
single channel rambus opeates at 400 mhz
david

[MadMan007]

Well, that first reply is incorrect in so many ways I won't even bother trying...

Anyway, the problem with running a 133 FSB with RDRAM has less to do with the memory itself than with the memory frequency controller on the motherboard. RDRAM has a frequency timing module or something on the motherboards that generates the 400 MHz signal and coordinates the memory timings. Not many of these units used on mobos when the i850 chipset first came out were capable of doing 133x4=533 MHz signals. Some people modded their boards with an after market chip capable of doing the higher frequencies. Maybe new revisions of motherboards have the chips capable of doing this now, I don't know. Check with the Intel section here.

I believe most RDRAM itself is capable of the 533MHz speed, but I am not sure since I was never interested enough in RDRAM to research that heavily myself. Supposedly the Samsung RDRAM is some of the best tho.

I know www.aceshardware.com did a 133 FSB RDRAM project a while back, go check it out.

[Dissolved]

just save your pennies for the 2200+ althon XP....
nuf said :D

[Turbo]

Well, I've read the article on Aces, as well a couple at Extremetech and Hardwareanalysis. Also I have zero problems what-so-ever running my TH7-II at 133 Mhz fsb, with Samsung PC800 RDRAM at 4x (PC1066 effectively). I think it will prove to be more troublesome getting the 1.6A's and 1.8A's to a 133 Mhz fsb on a RDRAM mb, as hardly any of them supply the neccessary voltage needed for a 33% overclock. Also Intel is supposedly binning the cpu's big time from what I've heard, so the 1.6A's and 1.8A's were the ones that couldn't quite make it to 2 Ghz. A 1.5 or 1.6 Williamette D0 stepping is probably more likely to hit a 133 Mhz fsb. You could, of course do a voltmod on the MB if needs be ;) If you have a month or two, wait it out and see how initial results are with the "small" Northwoods, and maybe PC1066 will be available then. If you must buy RDRAM now, I highly recommend Samsung PC800's.

[littlerichie]

dont bother is a good answer for you !
because you do not know jack about rdram
there were 2 types of rdram
the first was singl channel which was 400 mhz
the newer 1 is pc800 rambus which is 800 mhz
rdram with the p3 was not popular because of the high price
of rambus and also the p3`s 133mhz fsb could not take advantage of
the pc800`s operating fequency.

[Maximus Nickus]

Language please.

[MadMan007]

Originally posted by littlerichie
dual channel rambus operates at 800 mhz
single channel rambus opeates at 400 mhz
david

Originally posted by littlerichie
dont bother is a good answer for you !
because you do not know jack about rdram
there were 2 types of rdram
the first was singl channel which was 400 mhz
the newer 1 is pc800 rambus which is 800 mhz
rdram with the p3 was not popular because of the high price
of rambus and also the p3`s 133mhz fsb could not take advantage of the pc800`s operating fequency.

Well then you have forced me to reply. Also, this is not meant as a flame, I just want to give complete and accurate info. It also seems from your posts that English may not be your first language, so maybe we can just chalk this all up to a language barrier. :)

In your first post, you say that single and dual channel Rambus operate at different frequencies. This is not true, the RAM itself is always running at 400MHz (remember the P4 has a 100MHz quad-pumped bus=400MHz) and one channel provides 1600Mb/s of bandwidth, 4 bits/s (or maybe bytes...) x 400MHz. RDRAM delivers 2 b/clock cycle, hence its name " PC800." Since it is 400MHz quad-data rate, it is equivalent to saying 800MHz double data rate RAM. This would be the same as saying that PC2100 DDR runs at 133MHz double data rate and call it 266MHz. It is all semantics.

The rambus chips themselves do NOT run at 800MHz though, and both dual and single channel RDRAM modules run at the same speed. If this were not the case you would have to buy different RDRAM depending on if you had a single (i840) or dual channel (i850) board, when in fact all you have to do is get two identical modules to run a dual-channel board.

Since the RDRAM modules are identical between dual and single channel, with dual channel you have two RDRAM modules running at 4b/s x 400MHz=1600Mb/s x 2 channels=3200Mb/s bandwidth. This is why the i850 (dual channel) runs the P4 so much better than i840 (single channel.) The P4 is a bandwidth hog and needs all it can get. For "PC1066" you have 4b/s x 533MHz=~2100Mb/s x 2 channels = 4200Mb/s total bandwidth.

You are right about the P3 not being able to benefit from RDRAM, because the P3 has a 133MHz FSB which gives it 1066 Mb/s processor bandwidth. In other words, it can only use a max of 1066 out of the 1600 even a single channel of RDRAM supplies, hence P3=RDRAM is a waste, especially with the lower latency of SDRAM.

If any of the above that I have posted is innaccurate please tell me, but try to use complete sentences if possible since the way you write is a little hard to understand exactly what you mean. The article here (http://www.aceshardware.com/read.jsp?id=45000217) at Ace's hardware is a very informative piece about actually achieving PC1066 with any RDRAM.

Again this is all academic to me since I seriously doubt I will ever build a system with RDRAM.