computer memory question

[SUBMAN1]

Originally Posted by AVGWarhawk

@subman1

I will have to check for sure what sticks I have but with that said, would it be best to just add a 1 gig along with a 512 stick of the same memory type for better performance?

More memory is always better. Doesn't help on a 32 bit system to go past 3 GB since you can only use extra memory beyond that point for the Windows kernel, but on an XP box, I'd not go anywhere less than 1.5 GB for the games today. On SHIV, you will notice a marked improvement with more memory, especially in the loading screens. 1 GB is just not enough anymore.

ONe thing I forgot to mention - if you have a dual channel system, you must used matched memory to get the full benefit out of it. That allows 4 transactions per clock cycle instead of the DDR (Stands for double data rate) 2 transactions per clock cycle.

3200 in a dual channel system can have a peak bandwidth of 6.4 GB/sec. Pretty fast for normal memory.

-S

PS. The way a dual channel system works is that it hits each module indpendantly in parallel. It is kind of like a RAID 0 drive system. In a single clock cycle, you hit both RAM modules independantly, so you can do 2 transactions on the first, and 2 transactions on the second, resulting in a total of 4 transactions, effectively doubling the normal RAM throughput - this is why you need 2 matched memory modules - they need to be the same size and same timing - preferably modules made from the same batch or manufactured together at the exact same time.

[AVGWarhawk]

Well that is the thing. I have two 512 sticks of memory. I think PC2700. So it would be OK to install 1 gig stick of PC2700 and 512 stick of PC2700 this configuration should work OK giving me 1.5 RAM?

[SUBMAN1]

Originally Posted by AVGWarhawk

Well that is the thing. I have two 512 sticks of memory. I think PC2700. So it would be OK to install 1 gig stick of PC2700 and 512 stick of PC2700 this configuration should work OK giving me 1.5 RAM?

Yes. But, if your system is dual channel enabled, this RAM will not work in dual channel and it will make you single channel only if you install it, effectively bring you back down to 2 transactions per clock cycle. Not a big deal though because this is fast enough. The benefits of more memory outweigh any negatives imposed here.

I doubt your memory that is installed is 2700 - that is if you are running at 3200 speeds. That is unless it has a heat spreader on it. The Athlon 3200 + XP's were all if not almost all running with a 200 MHz BUS and at 3200 speeds.

[AVGWarhawk]

Originally Posted by SUBMAN1

Yes. But, if your system is dual channel enabled, this RAM will not work in dual channel and it will make you single channel only if you install it, effectively bring you back down to 2 transactions per clock cycle. Not a big deal though because this is fast enough. The benefits of more memory outweigh any negatives imposed here.

I doubt your memory that is installed is 2700 - that is if you are running at 3200 speeds. That is unless it has a heat spreader on it. The Athlon 3200 + XP's were all if not almost all running with a 200 MHz BUS and at 3200 speeds.

Any idea how to find out if it is running at dual channels? Effectively I originally purchased the computer with 512 and just added similar RAM to make 1 gig. My plan is to remove one of the 512 and add a 1 gig in this slot.

[SUBMAN1]

Originally Posted by AVGWarhawk

Any idea how to find out if it is running at dual channels? Effectively I originally purchased the computer with 512 and just added similar RAM to make 1 gig. My plan is to remove one of the 512 and add a 1 gig in this slot.

It should tell you upon posting, that is if you don't have any graphic logo coming on to cover it up. If your board supports it, it will automatically be enabled if you computer thinks it can be. The first clue to finding out is to look in your motherboard manual. If you've lost it, get the motherboard model number and download a copy of the manual off the manufacturers site.

By the way, the only chipsets to really support dual channel only came from ATI or NVidia, so if you have a crossfire chipset (unlikely) or an NForce chipset up to rev 2 (Rev 3 I think was Athlon 64 only), then you have dual channel. If you are using a VIA chipset or soemthing else, then you probably don't have dual channel.

-S

Most current mobos support dual-channel these days. Mobo's that may not are those that don't have an even number of memory slots, i.e., three slots, although in that case they still may if two sticks populate the slots. Moreover, if the memory slots are color coded (with two slots being blue), this is an indicator that the mobo supports dual-channel. If single sticks populate two different color coded memory slots, then dual-channel will not be implemented. And if all slots of an odd number slot configuration are populated, then dual-channel will defacto be disabled.

The best way to determine dual-channel memory implementation/support is to look in the BIOS itself. Press DEL at boot-up, and then look in the memory configuration page. It should have an option to enable dual-channel. If its set to auto, then it'll be enabled if and when appropriate memory is found by SPD at boot time. The safest way to exit BIOS is to chose the "exit discarding changes" option (even if you don't think you changed anything).

Furthermore, it is never a good idea to mix memory timings of one's RAM. ALWAYS populate the board with identical timings. And in the case of dual channel, even pairs of similar timing & speed RAM in the appropriate slots. Memory speed is important, but even more important are the timings, e.g. 2-2-2-5, etc., you don't want to be populating the board with similar speed (but different timing) sticks of RAM. Not many BIOS have timing setups for each stick.

If you presently have 2x512MB PC2700 on the board, then you won't see much performance increase at all (unless you're doing memory intensive applicatoin use, e.g., sound, video, CAD, etc.) You may notice a performance increase if you scrap your existing 2x512 PC2700 and replace it with PC3200 (although I doubt that an 18% increase in RAM speed will be all that noticeable). However, if you run something like BOINC, that 18% will add up over time.

[SUBMAN1]

Originally Posted by Wxman

Most current mobos support dual-channel these days. Mobo's that may not are those that don't have an even number of memory slots, i.e., three slots, although in that case they still may if two sticks populate the slots. Moreover, if the memory slots are color coded (with two slots being blue), this is an indicator that the mobo supports dual-channel. If single sticks populate two different color coded memory slots, then dual-channel will not be implemented.

The best way to determine dual-channel memory implementation/support is to look in the BIOS itself. Press DEL at boot-up, and then look in the memory configuration page. It should have an option to enable dual-channel. If its set to auto, then it'll be enabled if and when appropriate memory is found by SPD at boot time. The safest way to exit BIOS is to chose the "exit discarding changes" option (even if you don't think you changed anything).

Furthermore, it is never a good idea to mix memory timings of one's RAM. ALWAYS populate the board with identical timings. And in the case of dual channel, even pairs of similar timing & speed RAM in the appropriate slots. Memory speed is important, but even more important are the timings, e.g. 2-2-2-5, etc., you don't want to be populating the board with similar speed (but different timing) sticks of RAM. Not many BIOS have timing setups for each stick.

He has an Athlon 3200. He only has 3 motherboard chipsets for his CPU in the day when that CPU was popular that supports dual channel. Nforce 1 and 2 and maybe a Crossfire based board.

By the way, I have yet to see a BIOS that allows you to enable or disable dual channel (though they probably exist on cheaper motherboards since most motherboards will auto-detect it). ALso, I've only seen one motherboard that only has 2 RAM slots that supports dual channel. almost all of them have 3 or 4 ram slots, with the majority being 3. It depends on the memory configuration or not as to whether or not it is enabled. slot 2 & 3, if used alone, will enable dual channel for example (its almost always backwards on 3 slot configurations), and using slot 1 & 2 is not dual channel enabled. However if all 3 slots are used, it will also disable dual channel. On later 4 slot motherboards, you were able to use 2 seperate sets of dual chaneel enabled memory.

Anyway, to figure out how to enable dual channel, or for proper memory configurations, this is why you need the manual.

Dual channel is not as big a deal as more memory however. The speed improvements for the faster ram are not really noticeable, but it is probably measurable. If this was video card RAM however, that might be a different story.