PC RAM question

[BoringSupreez]

I have an oldish PC that I bought some RAM for recently. I already have one stick of 1GB 4300 (refers to the speed) RAM installed, and the chip I have coming is 2GB and 5300. I read that using both types of memory at the same times slows down the faster chip to match the slower one. I was wondering: would it be better overall to use both, or just the 2GB stick for the faster speeds?

[vlame]

mostly speed doesn't really matter. what are you trying to do with it?

[BoringSupreez]

mostly speed doesn't really matter. what are you trying to do with it?

Play games. My PC currently has trouble running stuff from 2006 and up, so I'm upgrading the RAM and video card.

[vlame]

oh then ram speed will matter. but i would keep all 3gb.

[neilencio]

I have one of my extra PCs using a PC2-6400 as a PC2-5300 (I reduced the timing because I get random freezes when set to ddr 800 mode) , there's a speed hit, but it's negligible and I only notice it in applications that load to and fro from system RAM a lot (in my case, I only notice it in PCSX2's software mode, because it has an fps counter. I would be lying if I say that I can easily notice it anywhere else)

As for games, I doubt the speed hit will be that noticeable, since games nowadays usually rely more on textures being loaded to and from the vidcard's RAM during play. However, you'll definitely notice the slower startup and loading IF you only use one mem module just to get access to faster response times. Games will probably do a lot of hard disk swapping, which is a hell of a lot slower.

I believe the tradeoff is

Smaller, but faster RAM:

- game/maps will load slower during start
- the game itself will run faster (barely noticeable?)
- but you get stutters or skips in the middle of the game if the game needs to swap to your hard disk

Larger, but slower RAM:

- game/maps will load faster when starting
- the game itself will run a little bit slower (barely noticeable?)
- you get smoother experience during gameplay because the game doesn't need to do disk caching and swapping so much.

TL;DR version: I believe you won't notice the effects of slightly slower RAM, but you will certainly notice the effects of less available memory.

[BoringSupreez]

Alright, thanks, I'll use both chips then.

[Zing]

In many cases, having "slower" RAM isn't significantly slower, and is often faster!

While your PC5300 is rated for higher speed than PC4300, the chips can't actually handle the full speed difference. For the PC5300 to run at the faster speed, a longer delay needs to be introduced between the time the system asks for data, and the memory chips can supply it. This is usually referred to as the CAS or CAS/RAS timing. The PC5300 will have a higher (slower) CAS timing than PC4300.

Ultimately, what you have is data that takes longer to retrieve from the memory chips, but travels slightly faster along the data path to the CPU. Like I said, sometimes the increased data speed makes up for the increased access time, but sometimes it does not.

In short, I wouldn't worry about lowering the speed of the PC5300. The only issue you will find is that "dual channel mode" on the memory will be disabled. I'm fairly certain that you need identically sized DIMMs in pairs for it to be enabled. Despite the name "dual channel" suggesting a doubling of speed, real-world tests show it only boosts speed about 10%, which is admittedly still significant.