TOM! Please give us P4 PC600 vs P4 PC800 ASAP!

[Guest]

Well since the last can of worms I opened is almost cleaned up, let's get a fresh one going. Currently many OEMs are shipping P4s with PC600 and PC700 RDRAM to save costs. However, a bench done with an i850 with only 1 channel functioning seems to indictate P4 is more memory sensitive than any CPU we've seen so far.

Aceshardware's been discussing this and so far the consensus is the new cache design of the P4 makes execution performance fall off a cliff as soon as memory performance goes down, much moreso than P3 or Athlon.

Please compare the P4 against itself so we know whether the major OEMs are ripping people off with sub-par machines for the sake of a few dollars in memory.


-- Toby Hudon (in case you forgot who Gldm is. )

 

[Guest]

should be interesting

"whether the major OEMs are ripping people off with sub-par machines for the sake of a few dollars in memory."
ooh! buying P4 now is already a rip off and if ppl are dumb enough to get one with only PC600/700 RDRAM, I think they are hopeless.

 

[Guest]

It seems that the p4 is very dependent on a high bandwidth memory system(i.e.DRDRAM). I believe(no one really knows-except intel) that the failure of drdram to penetrate mainstream machines may hurt the p4's performance in the future.
Any benchmarks(DRDRAM 600/700 mhz) run by Dr. Tom will show severe performance penalties(although no one knows until all the ballots are counted, oops! I mean the benchmarks done).

The p4 architecture is made for DRDRAM and high speed DRDRAM at that.
DDR RAM is the solution for the near future and the p4 will suffer for it.

I hope AMDSUX... replies to this message I love reading his/her rants.

"in the end it's all about holding your breath"

 

[Guest]

I think you are right. All the people who do not know the difference between PC600 and PC800 RDRAM "should be shot!".

Seriously...

We obviously are in the minority when it comes to computer knowledge. I will bet that 90% of the people who by computers don't know, and don't care. They should, but they don't. So it comes down to education. Who will be the one to tell the world that they have to spend all that extra money for maybe 10 to 15 percent performance increase. We know different, but I really think that most won't really care that much (Not for that kind of money!).

 

[Guest]

I only wonder why PC-600 and PC-700 were EVER created as standards... I know I'm only asking this question from a technical point of view, because it has a LOT of "pros" going for it if we speak about a market point of view...

Seoman. Newbie at last!

 

[mpjesse]

It seems like everyone is forgeting that RDRAM has been out for about 8 months. That's an eternity in the computer industry. PC600 will phase out soon.

-MP Jesse

 

[Guest]

One would hope PC600 would "phase out" but it doesn't seem to be doing so. Also, I'm not thinking performance penalties of 10-15% like PC100 vs PC133, I'm thinking 20-40%. That's a BIG hit. Alot of people base their buying decisions from what they hear from more informed users. The conclusions on many of the wider read hardware sites often filter down into the general public perception of a product. I consider what sites like this one do as a service to the public to keep at least some people informed of the reality, so they can inform others and help them make better decisions, as I try to do with alot of people who come to me for computer advice.

 

[Guest]

However, there is a chance that P4 is going to get an upgrade on the RDRAM side of things. Didn't Samsung and Rambust both bragged about 1Ghz RDRAM? Combining this with Tom's finding of pretty overclockable P4's FSB then we get a good 125Mhz FSB for a total of 4Gb/s throughput.

This will help, but at what cost?

 

[Guest]

Hey~~The idea of giga hertz RDRAM + P4 really turns the overclocking side of me on (yes yes I know damn sure I can't afford any of the items mentioned above in a million years)

Without even modding P4's multiplyer, 15(?)*125Mhz = 1875Mhz AND 4Gb/sec bandwidth!! If it's not the cost, this will be the casual OCer's Toy of the Year

 

[Guest]

The problem is, DDR SDRAM, while cheaper, does not have the bandwidth of RDRAM - and P4 appears to be EXTREMELY bandwidth-dependant. It is unknown, however, what effect will DDR SDRAM's lower latency will have on P4 performance.

 

[Guest]

1."The problem is, DDR SDRAM, while cheaper, does not have the bandwidth of RDRAM"

no. actually, as far as data throughput (i think this is what you meant as "bandwidth") is concerned, DDR is just a little bit behind RDRAM.

PC800 RDRAM has a data throughput of 1.6Gbytes/s. a dual-channel PC800 RDRAM config, 3.2Gbytes/s.

PC600 RDRAM, 1.2Gbytes/s. a dual-channel config, 2.4Gbytes/s.

PC2100 DDR, 2.1Gbytes/s, just about a bit lower than a dual-channel PC600 RDRAM config while way above the single-channel PC800 RDRAM config.

just think of "dual channel PC2100 DDR" that is probably on the way: 4.8Gbytes/s! amazing!! plus the latency factor, such a config will leave DC PC800 RDRAM config way in the dust!!

2."and P4 appears to be EXTREMELY bandwidth-dependant."

this is a bitter-sweet truth, while there is more bitter than sweet.

3."It is unknown, however, what effect will DDR SDRAM's lower latency will have on P4 performance."

generally speaking, latency is more important.

more to say: P4 is actually designed to live with RDRAM --actually, only Dual-Channel PC800 RDRAM. think about the "Quad-Pumped" FSB. its data throughput is also 3.2Gbytes/s, exactly the same as the throughput of a Dual-Channel PC800 RDRAM config. without this match (balance), other configs will simply kick the crap off into severe "data anaemia".




-----------------------------
Some are ignorantly happy,
While some, happily ignorant.

 

[Guest]

There's a saying I like to keep in mind sometimes. "You can always make more bandwidth, but latency is forever." I forget where it's from, but it's true. Take nVidia's upcoming Crush chipset for Athlon. 128bit DDR interleaved SDRAM interface = 4.2GB/sec @133mhz, and it might OC to 166 for 5.3GB/sec on some of the newer Infineon or Micron DIMMs. Won't that be fun? Slap in a Duron, HD, and CD and it's a ready to go game system.