Questions about using different types of Memory

[pradeep1]

I bought an Asrock 4CoreDual-VSTA mobo because it supports DDR400/333/266 and also DDR2 667/533 RAM. I am currently using it with an e4300 which has a FSB of 800, and I am using DDR400 RAM with this processor. All is good.

I saw a deal on newegg for two sticks of memory and the specs are 240-Pin DDR2 667 (PC2-5300) RAM.

http://www.newegg.com/Product/Product.a...m=N82E16820161677&CMP=AFC-Bensbargains

How will this affect my system if I buy this pair and use the DDR2 667 memory with a processor that has FSB of 800? Don't the DDR rates have to be half of the FSB for things to work okay? If I use DDR2 667 RAM, will it downclock to DDR2 400 or just not work?

It's been a while since I fooled with RAM and I have forgotten how this works.

 

[pradeep1]

no one?

 

[Sdiver2489]

Your ram will still be a bottleneck...just get these and call it a day

http://www.newegg.com/Product/Product.aspx?Item=N82E16820231098

 

[pradeep1]

Originally posted by: Sdiver2489
Your ram will still be a bottleneck...just get these and call it a day

http://www.newegg.com/Product/Product.aspx?Item=N82E16820231098

So DDR2 800 will pair well with a FSB 800 CPU? My mobo only supports DDR2 667, so I'll be buying these and underclocking them to 667, right?

 

[Roguestar]

They'll automatically run at DDR2-400 when you put them in, and scale up with your FSB should you decide to overclock. That they're DDR2-800 means that until you push the FSB to 400Mhz actual (it runs a 200Mhz actual), you won't need to overclock your RAM.

 

[pradeep1]

Originally posted by: Roguestar
They'll automatically run at DDR2-400 when you put them in, and scale up with your FSB should you decide to overclock. That they're DDR2-800 means that until you push the FSB to 400Mhz actual (it runs a 200Mhz actual), you won't need to overclock your RAM.

Thanks Roguestar for the info. Will I notice a difference between DDR-400, which I have currently, and DDR2-400? Also, I am currently running the mobo FSB at 300 in overclock, so my current RAM is overclocked by 50%, but these newer sticks will actually be underclocked.

Interesting.

 

[Roguestar]

Probably not, really. It's not a huge jump. You might notice a slight improvement in games if it were running at DDR2-800, so you can go into your BIOS and change the memory ratio. This means that the memory runs faster than the FSB so you can run your memory at its rated speed, then you'll be tapping into the otherwise wasted memory bandwidth. Setting it to 1:2 means that your FSB will run at 200MHz actual and your DDR2 at 400Mhz actual (rated as DDR2-800 and therefore the stock speed of your RAM).

Edit: if you're running overclocked to 300MHz then you can set the FSB/memory multiplier to 3:4 and run your RAM at 400MHz (DDR2-800 speed).

 

[pradeep1]

Originally posted by: Roguestar
Probably not, really. It's not a huge jump. You might notice a slight improvement in games if it were running at DDR2-800, so you can go into your BIOS and change the memory ratio. This means that the memory runs faster than the FSB so you can run your memory at its rated speed, then you'll be tapping into the otherwise wasted memory bandwidth. Setting it to 1:2 means that your FSB will run at 200MHz actual and your DDR2 at 400Mhz actual (rated as DDR2-800 and therefore the stock speed of your RAM).

Edit: if you're running overclocked to 300MHz then you can set the FSB/memory multiplier to 3:4 and run your RAM at 400MHz (DDR2-800 speed).

Very good info. Thanks for your help.

If I run this at the full DD2-800, then I should definitely notice an improvement!

 

[Aikouka]

Originally posted by: Roguestar
They'll automatically run at DDR2-400 when you put them in, and scale up with your FSB should you decide to overclock. That they're DDR2-800 means that until you push the FSB to 400Mhz actual (it runs a 200Mhz actual), you won't need to overclock your RAM.

I thought the chipset had automatic ratio settings so it would leave the memory running at 667 and just adjust the ratio automatically.

 

[pradeep1]

Originally posted by: Aikouka

Originally posted by: Roguestar
They'll automatically run at DDR2-400 when you put them in, and scale up with your FSB should you decide to overclock. That they're DDR2-800 means that until you push the FSB to 400Mhz actual (it runs a 200Mhz actual), you won't need to overclock your RAM.

I thought the chipset had automatic ratio settings so it would leave the memory running at 667 and just adjust the ratio automatically.

I really don't know what would happen. Officially, the mobo only supports DDR2-667.

 

[Roguestar]

Originally posted by: Aikouka

Originally posted by: Roguestar
They'll automatically run at DDR2-400 when you put them in, and scale up with your FSB should you decide to overclock. That they're DDR2-800 means that until you push the FSB to 400Mhz actual (it runs a 200Mhz actual), you won't need to overclock your RAM.

I thought the chipset had automatic ratio settings so it would leave the memory running at 667 and just adjust the ratio automatically.

It'll downclock the memory to match the speed of the FSB corresponding to his CPU. Perhaps the motherboard specification says that because that's as high as they tested it with DDR2 at the time; when most P965 boards came out there wasn't very high-speed DDR2 and most still hasn't been JEDEC certified (except now for DDR2-800).

 

[pradeep1]

So what you are saying is that my mobo may only officially support DDR2-667, but will run DDR2-800?

 

[pradeep1]

bump for eyes

 

[Roguestar]

Originally posted by: pradeep1
So what you are saying is that my mobo may only officially support DDR2-667, but will run DDR2-800?

If it can't run it at DDR2-800 it'll run it at DDR2-667.

 

[pradeep1]

Originally posted by: Roguestar

Originally posted by: pradeep1
So what you are saying is that my mobo may only officially support DDR2-667, but will run DDR2-800?

If it can't run it at DDR2-800 it'll run it at DDR2-667.

So then there is no benefit of paying extra money for DDR2-800 as compared to DDR2-667 as a previous poster had suggested. But then again, the better quality G-Skil DDR2-800 may go a longer way when I upgrade.

 

[mercanucaribe]

Is there any performance benefit to using DDR1066 with a CPU with a 1066mhz FSB? DDR800 provides no benefit over DDR533, but could DDR1066 actually help because it's 1:1 with FSB and not some odd number?

 

[Roguestar]

Originally posted by: mercanucaribe
Is there any performance benefit to using DDR1066 with a CPU with a 1066mhz FSB? DDR800 provides no benefit over DDR533, but could DDR1066 actually help because it's 1:1 with FSB and not some odd number?

The numbers are multiplied by various things over the actual speed they run at. The 1066 FSB is actually a 266MHz FSB but sends 4 bits per cycle instead of one, hence the term "quad-pumped" and the enlarged figure. DDR2 speeds are doubled as it sends 2 bits per cycle, so DDR2 at 533MHz (DDR2-533 or PC2-4200) is all that's needed to run 1:1 with a 266MHz FSB. DDR2-1066 runs at an actual speed of 533Mhz, double the FSB speed of a normal core 2 duo. You can set the memory/FSB ratio by changing the multiplier in the BIOS, (which may say 2.0 when meaning a 1:1 ratio) to 4.0, doubling the speed of the memory from the default DDR2-533 to DDR2-1066.

 

[mercanucaribe]

Originally posted by: Roguestar

Originally posted by: mercanucaribe
Is there any performance benefit to using DDR1066 with a CPU with a 1066mhz FSB? DDR800 provides no benefit over DDR533, but could DDR1066 actually help because it's 1:1 with FSB and not some odd number?

The numbers are multiplied by various things over the actual speed they run at. The 1066 FSB is actually a 266MHz FSB but sends 4 bits per cycle instead of one, hence the term "quad-pumped" and the enlarged figure. DDR2 speeds are doubled as it sends 2 bits per cycle, so DDR2 at 533MHz (DDR2-533 or PC2-4200) is all that's needed to run 1:1 with a 266MHz FSB. DDR2-1066 runs at an actual speed of 533Mhz, double the FSB speed of a normal core 2 duo. You can set the memory/FSB ratio by changing the multiplier in the BIOS, (which may say 2.0 when meaning a 1:1 ratio) to 4.0, doubling the speed of the memory from the default DDR2-533 to DDR2-1066.

Yep, I know what it means, I just want to know if you get a performance boost from having a final 1:1 FSB:Memory ratio.

 

[Roguestar]

Oh, heh, sorry. Yeah, doubling the memory bandwidth will give you a performance increase but whether it'll be really noticeable the jury is still out deciding. If there are games you're being limited by RAM in then yeah you might see a benefit in terms of FPS, and perhaps switching between big applications when multitasking, but not nearly the kind of performance gain as upgrading or overclocking your processor a little, or going up one step in the graphics card department.

Edit: Oh, and DDR2-533 is technically a 1:1 FSB ratio, DDR2-1066 is a 1:2 ratio FSB/memory.