RAM vs. FSB speeds

[nqc]

Not sure whether to post this here or in the motherboards forum, but here goes:

I'm attempting to buy a new PC on Dell.ca, and as part of their Dimension 8400 package, they offer Intel P4 CPUs at 3.8GHz, with an 800 MHz FSB. However, they offer two speeds of DDR2 SDRAM for this CPU -- 400 MHz and 533 MHz, the latter of which they seem to claim will give better performance. I'd understood that Intel CPUs worked best when their FSB and RAM speeds were matched 1:1.

Is this correct, or could I in fact get a speed improvement out of the 533 MHz RAM, even though the FSB is limited to 800 MHz?

Thanks in advance for any info, folks.

 

[jammydodger]

Dual channel DDR2 533Mhz will will effectivly run at 1066Mhz which is higher thanyour FSB. However it will still give a slight performance increase (at least with synthetic benchmarks), im not totally sure why this is (it seems impossible). The performance increase probably isnt worth the money though, in fact DDR2 isnt really worth the money since 533Mhz DDR2 gives about the same performance as 433Mhz DDR1 (which is significantly cheaper).

 

[nqc]

Appreciate the input.

Unfortunately, there really isn't any choice when buying a Dell as to the type of RAM you get -- if you're buying a Dimension 8400, you get various speeds of DDR2, and that's it. In fact, everything above the Dimension 3000 series uses DDR2 RAM -- if I want the otherwise stellar performance of the higher-end models, I'm stuck with DDR2.

Thus, I'm trying to discover if 4 Gigs of 533 MHz DDR2 RAM is worth the extra $100.00 CDN, over and above the $1,650.00 CDN you pay for 4 Gigs of 400 MHz DDR2 RAM, since they're both offered for Intel chips with 800 MHz FSBs. The price difference is +6.1% -- I wonder if the performance gain is more or less?

Thanks again. Guess I'll spelunk around some more via Google to see if the question can be answered a little more definitively.


Garth

 

[Crashman]

I think the DDR2 400 and DDR2 533 are probably running the same timings, which would make the real-time latency lower (because the cycles occur faster).

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[jammydodger]

I was comparing DDR1 at 433Mhz to DDR2 at 533Mhz, not DDR2 400 and DDR2 533.

 

[jammydodger]

4Gigs of RAM, what are you using this system for? Its a bit of a bummer that you are stuck with DDR2, especailly as DDR2 400Mhz will prob perform quite a lot worse than DDR1 400Mhz. Ah well, If I were you I would get the 533Mhz DDR2.

Is building your own system not an option?

 

[nqc]

The system will be used for rendering (CPU-based, *not* graphics-card-based), as well as Photoshop manipulation. PS only uses a max of 2 Gigs, but it's nice to have it loaded up and still have plenty of headroom left for other apps (I typically have four or five apps loaded at a time, several of which are total memory hogs -- Poser 5, for instance).

As for building my own system, been there, done that. Waste of my time, really -- systems I built (or had built for me) in the past tend to be built from parts available to "Tier II" manufacturers/distributors, while the cutting-edge stuff (particularly latest-and-greatest Intel CPUs) are available only to "Tier I" manufacturers such as Dell. Perceptually, any Dell I've bought in the last five years has smoked the ass of any home-brewed and/or locally-built system I've compared it to. Dell makes nice, fast, stable systems -- but they also tend to lock you in to very few choices.

I'm probably gonna wait and live with the limitations of my existing systems -- later in 2005, scuttlebutt has it that new latencies will be applied to DDR2 RAM which will make it much more performance-comparable to DDR. We'll see, I guess...


Garth

 

[Crashman]

Uh, Dell offers inferior performance parts. Their video cards for example are usually underclocked and specially made for Dell, to be cheaper. Dell's mission is to provide a system that lives for 3 years with minimal problems, not to build the fastest thing they can. As long as it doesn't affect quality, they'll sacrifice performance in order to offer lower prices.

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[mozzartusm]

The only way to know for sure that you are getting the best parts is to build one yourself.

 

[jammydodger]

Dell can get hold of the newest and fastest Intel parts, but that doesnt mean it can can hold of the best parts from any other manufaturer. Have you thought about getting an Athlon64/FX? You could prolly build a faster AMD system for less money, and it will be just as reliable as the intel one.

 

[Cybercraig]

Dell builds a decent low cost machine and fairly reliable servers, but Betsy here pounds my in-law's 560 Dell by almost 5,000 in Aquamark 3. As far as having no access to the latest CPU's, WTF are you talking about?

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