Dimension 8400 memory upgrade question

Hi Mrmga1,

Your specs <ADMIN NOTE: Broken link has been removed from this post by Dell> say 400 or 533 MHz for RAM, so I would think the RAM would run at 533 is your removed the PC2-3200 RAM. I can't believe 3GB running at the slower speed would be better than 2GB at the faster speed. However, it would be easy for you to verify both the actual RAM speed as well as the performance and make your own decision.

Osprey -

The specs are confusing. Doesn't a 533 MHz speed correspond to a PC2-4200 card? Is my computer limited to 533 MHz even if I put in PC2-5300 cards (rated at 667 MHz by Crucial)? More importantly, why would Dell themselves (the web site recommendation based on my service code and confirmed by "chat") recommend the 800 MHz cards?

Regarding your second comment, how do I verify actual RAM speed and performance? (I'm a novice at this stuff.)

You're correct. If you mix RAM with different speeds, it will all run at the speed of the slowest RAM.

I have an 8400 with a mix 2 GB of 533 mHz RAM and 1 GB of 667 mHz RAM (all from Crucial). The original RAM failed so I replaced it with 2 GB of 533 mHz RAM. Subsequently added 1 GB of 667, which wasn't available when I bought the 2x1GB 533 mHz. At least for me, there are fewer hard drive access cycles (eg, access to the Windows Page file) so it definitely runs faster, even though it's all running at 533 mHz.

I suspect the chipset in the 8400 can handle RAM running at 667 mHz (asssuming it's not mixed with slower RAM), but that RAM didn't exist when the 8400 came out. And Dell doesn't update specs.

Keep in mind that RAM speed is more than just mHz. There's also a "CAS latency"' factor. The lower the latancy, the better. The 667 mHz RAM in my system has a latency of 5 when running at 667 mHz, and a latency of 4 at 533 mHz. So does the lower latency make up for the lower mHz...? ?

You can download free CPU-Z to check out what's going on under the hood, including RAM speed.

Ron

Ron -

I suspect the chipset in the 8400 can handle RAM running at 800 MHz (let alone 667 MHz) since both Crucial and Dell say it can. That brings me to my original question: Is 2 GB of memory at 667 MHz better than 3 GB at 400 MHz?

I downloaded and ran CPU-Z and got confusing results. It shows 512 MB cards in slots 1 and 3 (and 2 and 4 empty) but the 8400 Service Manual says 1 and 2 are paired and 3 and 4 are paired. CPU-Z also says each PC2-3200 board has a "maximum bandwidth" of 200 MHz. Shouldn't that be 400 MHz?

Mike

The only way you'll know for sure is to do some benchmark tests first with the old RAM alone, then after adding the new RAM, and then after removing the old RAM. There are a number of free, shareware and paid benchmarking utilities available on the net.

As for the slot numbers , it's all in how you count slots. Slots 1 and 2 are paired for RAM installation (note color-coding on the slots), but if you look at the motherboard itself, slot #2 is actually the 3rdphysical slot, counting from the CPU.  The slot closest to the CPU is #1. Look at the System Board Components drawing here. 

<ADMIN NOTE: Broken link has been removed from this post by Dell>

You're forgetting the 2x multliplier. Take whatever number CPU-Z reports and multiply by 2. So 400 mHz RAM is  listed as 200 mHz; 533 mHz is listed as 266 mHz and 677 mHz is listed as 333 mHz.

Ron

You are correct, I am forgetting the 2x multiplier. I believe that's what the "2" in DDR2 means...

If I find that removing and adding memory cards is easy (for me), I will try to benchmark each configuration as you suggest. If I find it difficult (I've never opened a computer case before), it may be a one shot deal; I'll pick a configuration and go with it. In that case I'll go with the 2 x 1GB @ 667 MHz configuration and enjoy the greater speed. 2 GB should be enough for me; I got along fine with 1 GB until I installed Dragon Naturally Speaking (speech-to-text software) which is a huge memory hog -- about 300 megs of RAM.

Thanks again for your advice!

Mike

Always power off, unplug, and press/hold power button for ~15 sec before removing/installing any hardware. And when all else fails, read the manual. :emotion-4: 

<ADMIN NOTE: Broken link has been removed from this post by Dell>

Ron

Update:

I called Tech Support at Crucial and asked the rep his opinion on 2 GB @ 667 MHz vs. 3 GB @ 400 MHz. Without hesitation, he said go with the 3 GB memory. While the difference in memory speed would be detected by benchmark tests, he claims research shows overall performance would not be noticeably improved. He sounded very knowledgeable.

My conclusion is that there is no "right" answer but I'll be happy with either upgraded configuration.

Mike

Mike,

Sounds like a plan. Please let us know how the upgrade goes.

Ron & Osprey - Thanks for your help.

Mike, Sounds like a plan. Please let us know how the upgrade goes.

I finally got around to the memory upgrade today (added 2 x 1 GB PC2-5300s to the existing 2 x 512 MB PC2-3200s.) I carefully followed the instructions and had no problems other than the new memory cards requiring much more pressure to seat properly than I expected. While I was inside the case, I used compressed air to blow out dust and there was plenty of it. Luckily, I did that part of it outside otherwise I would have had a mess in my office. The 8400 seems to run quieter now.

So far I don't notice any improvement in performance, but the real test will come when I open up Dragon Naturally Speaking (a huge memory hog) while other programs are open.

Thanks again for your help.

Mike

:emotion-21: