RAM Timings vs. Bandwidth

[br3nd064]

Does anyone have an opinion on which type of ram offers better performance?

DDR2 800Mhz @ 4-4-4-12 or DDR2 1066Mhz @ 5-5-5-15

I've reviewed several benchmarks and they seem to say lower timings are better for most 3D games, while the higher bandwidth is better for programs that require a lot of ram (i.e. Photoshop). Is this correct?

Thanks

--
br3nd064

 

[iluvgillgill]

it all depends on your fsb if you running intel system

full spec please?

 

[outlw6669]

Does anyone have an opinion on which type of ram offers better performance?

DDR2 800Mhz @ 4-4-4-12 or DDR2 1066Mhz @ 5-5-5-15

I've reviewed several benchmarks and they seem to say lower timings are better for most 3D games, while the higher bandwidth is better for programs that require a lot of ram (i.e. Photoshop). Is this correct?

Thanks

--
br3nd064

That is pretty much it.
Unless you are using a program that shuffles large amounts of data in and out of the RAM, the extra bandwidth accounts for squat. The latency (first of the 4 numbers) specifies how many clock cycles it will take from requesting data to returning data. With this in mind, you can see that CL4 DDR2 800 and CL5 DDR2 1066 are virtually identical.

For some light reading on the matter, see the following links.

How memory frequency affects latency
TTR's Guide to Determining Optimum Overclocked System Performance Points
Anandtec's RAM FAQ
Understanding RAM Timings

Hope this helps!

 

[V3NOM]

well if you're only running at 400MHz FSB that extra bandwidth is wasted...just run in 1:1 and tighten timings as much as possibly -_-

 

[halister_one]

Strictly speaking, the 1066MHz ram with CAS5 should be faster, however performance is also largely based on the FSB.

To figure out what settings are theoretically faster, take the reciprocal of the memory frequency and multiply it by the CAS (first number).

1/800 x 4 = .005
1/1066 x 5 = .00469

The lower the result, the faster the ram makes one cycle, indicating better performance. That being said, when it comes to reality, the difference between the two is negligible.

 

[bobbknight]

It hard to argue with the graph from outlw6669.
So look at what you want to do and then buy a bunch of DDR2 800 like i did.
I mean you can get 8GB of DDR2 for about $200 and run a 64bit os and rock your world.

 

[V3NOM]

halister,if the FSB is only 400, then that extra 266 MHz the 1066 has compared to the 800 is completely useless as it is just sitting around waiting for the FSB! this is seriously the last time i'm saying this... getting too aggravated by it

 

[br3nd064]

well if you're only running at 400MHz FSB that extra bandwidth is wasted...just run in 1:1 and tighten timings as much as possibly -_-

That is what I'm doing right now. The FSB and ram are both at 400Mhz. I was reading reviews and that seemed to make the most sense.

Thanks for the help.

--
br3nd064

 

[halister_one]

halister,if the FSB is only 400, then that extra 266 MHz the 1066 has compared to the 800 is completely useless as it is just sitting around waiting for the FSB! this is seriously the last time i'm saying this... getting too aggravated by it

That's why I said "performance is largely based on the FSB". And he didn't state he's gonna run 400MHz FSB.

 

[V3NOM]

err you did....

 

[sportsfanboy]

There's more to it than just fsb/ram ratio, or simply the faster the fsb, the more performance. Ram to some degree controls the latency of your system, even when varying the fsb speed. Memory timings and frequency go hand to hand, when going for the lowest possible latency times.

When running at 1:1, or no divider, you put less stress on the memory controller, and no latency penalty will ensue. However it has been proven that higher speed ram can overcome latency penalties that ensue by using a divider.

So using 1:1 ratio is not always the fastest solution.

 

[iluvgillgill]

show us some actualy number shows 1:1 is not the fastest solution on a INTEL system! on amd of course the higher the ram speed the better. timing only affect latency where as speed is totally depend on the DSB bandwidth regardless how fast the ram is.

 

[sportsfanboy]

I think you miss understood the above post. 1:1 is the fastest when the frequency is the same. Meaning... When testing with the same frequency ram setting. What I said was, when using higher frequency ram,
memory latency CAN (not always the case, and depends on the divider used and speed of the ram) be overcome by the higher speed ram.

 

[iluvgillgill]

even will 333FSB along with 667 ram it will have the same read/write speed as ram is running a different multiplier at the speed of 800mhz.you will only see decrease in latency but bandwidth will pretty much stay the same.