Upgrade yay or nay?

[freak1982]

I currently have 4 x 512mb sticks of Corsair value RAM 667 PC5300

I can get 2 x 1Gb sticks of Adata Extreme 800 PC6400

My CPU/board can support 800Mhz so the memory in my system is a bottleneck at the moment.

I know the upgrade route will be easier (ie 2Gb to 4Gb) but other than that not really sure if this is a worthy upgrade. Not planning any overclocking but wouldnt complain about a bit quicker system? Mainly use PC for games BF2, Oblivion and Dawn of War. Internet and Photo/Video Editing is a secondary.

Freak1982

 

[darious00777]

My opinion?

If you've got things running smoothly and there doesn't seem to be any real problem with what you're running, don't bother upgrading now.

If you want a little bit of a boost, go for the upgrade, could help a little bit, but I'm not sure by much.

For myself, moving my 553 rated RAM up to 667 helped things a bit. Had to go up on the CAS latency to make things a little bit more smoother. If you need to relax the timings over 667 you'll still see some boost.

Hope some of this helped.

 

[freak1982]

Yeah it did. You kind of had my strongest 'against' point in your first couple of lines. If everything is working smooth then whats the point. Just had a performance review so maybe if they want to pay me a bit more then I might treat myself.

Thanks for the help.

 

[zjohnr]

I currently have 4 x 512mb sticks of Corsair value RAM 667 PC5300
My CPU/board can support 800Mhz so the memory in my system is a bottleneck at the moment.

Why do you think your memory is a bottleneck in your system? If you're running your RAM at its rated speed then with dual channel you'd have a max theoretical bandwidth of ~10,300MB/s. If you're using the stock Core 2 FSB of 1066MT/s then the max bandwidth of the FSB is ~8,133MB/s.

The articles I've read that investigate how much performance is gained when only the speed of the memory in a Core 2 system is increased always indicate a gain of a few percent at most. This is a gain that is so small that it is doubtful you would be able to notice it. If the only reason you want to buy new memory is to run at DDR2-800 vs DDR2-667, then you'd be better off saving your money for a more meaningful upgrade later this year or next.

-john

 

[grifter33]

If your sig is accurate and you're running a 3.2ghz p4 at stock speeds with an 800fsb then your aren't even running your memory at full speed. If everythings stock, and nothings overclocked, then you're running a 200fsb (200 x quad pumped= 800.) Which means if your memory is running 1:1 then it's only running at 200mhz(assuming its dual channel), even though its rated to run at speeds up to 333.

Your current memory is not a bottleneck in any sort of way, and even allows you some extra room already should you decide to overclock. Buying faster memory when you aren't even near pushing the max speed your memory is capable of is possibly the biggest waste of money you could do.

 

[scorch]

I currently have 1gb of ram and was thinking of going to up to 2 gigs. However somewhere I read that using 2 sticks of memory is better than using 4 so I was going to sell the 2 512's and buy 2 1gb chips. I don't know if the peformance degredation is noticible between 2 and 4 sticks

EDIT: Well I just got a chance to play around with Vista. Woop de do. I can wait until november... XP is fine for me. I'll save my money and get my car stereo.

 

[freak1982]

I think that if everything is running well enough at the moment then there is no point in spending £100 to get it a little bit faster.

From what I can tell from the Cosair Basic memory guide (v. interesting but needs watching a few times, I have only seen it once), it goes:

CPU -->Northbridge -->Memory

So my current system is:

CPU -800Mhz->Northbridge -667Mhz-> Memory

So if I did get 800Mhz it would be:

CPU -800Mhz->Northbridge -800Mhz-> Memory

So the throughput would be higher, is this right or did i screw up somewhere? I am not new to PCs but i am a bit new to all this in depth stuff. Any help is welcome.

 

[zjohnr]

So if I did get 800Mhz it would be:
CPU -800Mhz->Northbridge -800Mhz-> Memory
So the throughput would be higher, is this right or did i screw up somewhere?

There are some underlying hardware tweaks that make the analysis a little more complicated.

First, the (default) clock speed of the FSB (Front Side Bus) which connects your CPU to the Northbridge (aka MCH for Memory Controller Hub) is 200MHz, not 800MHz. The 800 number comes from the fact that your FSB actually does 4 data transfers every clock cycle, not just 1. So the effective transfer rate is 800MT/s (Million Transfers per second ... or something like that) which is the FSB speed you're familiar with. The marketing folk like it because it's bigger.

Now the FSB has a width of 64 bits = 8 bytes. So when running the FSB at 200MHz it is capable of transfering a maximum of 8 bytes/transfer * 4 transfers/cycle * 200M cycles/second = 6.4GB/s. That's the maximum (theoretical) bandwidth of the FSB when it's running at the default speed for your CPU. (If I did the arithmetic correctly ... )

Since you've looked at the Corsair memory guide you already know about DDR meaning Dual Data Rate. So while your memory bus clock is running at 333MHz, the actual transfer rate is 2 transfers/cycle * 333M cycles/second = 666MT/s. That's why it's referred to as DDR2-667. Each transfer moves 8 bytes so the maximum effective bandwidth for the memory bus (ignoring latencies) is 8 bytes/transfer * 667 transfers/second = ~5300MB/s.

But your motherboard also supports the "Dual channel memory architecture". In dual channel mode there are actually two paths to memory, each of them 8 bytes wide. So each transfer can retrieve 16 bytes from memory, not just 8. When your memory is running at its rated speed of 667MT/s the maximum bandwidth is 16 bytes/transfer * 667M transfers/second or ~10.6GB/s. (I did the arithmetic wrong in my previous post. )

So the FSB bandwidth is 6.4GB/s << memory bandwidth which is 10.6GB/s.

Bottom line: If you want a faster system, keep saving your money and sometime later this year, after prices have dropped some more, move to (probably) an Intel Core 2 motherboard and CPU. Amazingly you can keep your current DDR2-667 memory and still get a lot better performance by changing to the Core 2 CPUs. All you need to run a Core 2 is DDR2-533. With DDR2-667 you could even overclock a little bit, in which case the Core 2 would definitely whomp what you're current using.

Or so my reasoning goes ...

-john, the ostensibly clueless redundant legacy dinosaur waiting to be corrected