Ram questions

Merlin5 · 1 Sep 2009 at 00:39

I've installed 2 x 2GB Patriot Viper PC2 6400 ram @ 800MHz. I'm on windows XP 32 bit, so I believe from what I've read that I should be able to have about 3GB or so of available ram. This is the ram I bought: http://www.overclockers.co.uk/showproduct.php?prodid=MY-010-PA&groupid=701&catid=8&subcat=

Windows system information tells me my total physical memory is 4.096.00 MB
But it says available physical memory is 2.58 GB. So, presumably, 32 bit only shows about 2.5GB ram and not 3GB+?

Also, from my mobos monitor app called Easytune 6, it shows ram details for slot 1, and ram details for slot 2 via a drop down box. Both slots show identical details. Per slot, it says 'Module size' 2048 MB, so both slots would also add up to the 4.096 MB. Where it says 'Max Bandwidth' it says 'PC2-6400 (400MHz)'. I thought each stick of 2GB ram was meant to be 800MHz, (spec: "These modules are designed to operate at 800MHz") or does it mean combined it's 800MHz as opposed to each module at 800MHz?

Rainmaker · 1 Sep 2009 at 02:33

32 bit will use and show 3GB minus system-allocated video RAM basically; in your case 2.5GB. You'll need to upgrade to x64 to get the full benefit - try Windows 7. Also, unless you've set them up wrong, DDR (double data rate) 400MHz = 800MHz.

That's as much as I understand, I'll let someone more knowledgeable come along later/in the morning

zapgod · 1 Sep 2009 at 02:50

so if i have 6gb of ddr3, and i have 2 graphic cards each at 1024

how many GB would i see?

dustofnations · 1 Sep 2009 at 03:16

@zapgod Graphics memory is addressed independently of system memory (when you are talking of discrete cards). Within windows 32 bit the OS can make use of only ~3GB of RAM (i.e. the DDR3).. However Windows 64 bit editions (xp, vista, win7) can use several hundred GB of RAM (so you would be fine).

Incidentally the maximum for a 64 bit system is simply 2^64 bytes

Merlin5 · 1 Sep 2009 at 03:17

Rainmaker said:
32 bit will use and show 3GB minus system-allocated video RAM basically; in your case 2.5GB. You'll need to upgrade to x64 to get the full benefit - try Windows 7. Also, unless you've set them up wrong, DDR (double data rate) 400MHz = 800MHz.

That's as much as I understand, I'll let someone more knowledgeable come along later/in the morning

Thanks. Ah, I didn't know DDR meant that. So if for instance I had bought the faster DDR2 PC2 8500, it would have said 'Max Bandwidth PC2-8500 (533MHz)', but you'd just double that up to 1066. Is that about right?

In task manager, it's telling me Physical memory (K)3406252 and Available memory (K) 2803000, that's about 3.4GB and 2.8GB so that sounds like what you said.

dustofnations · 1 Sep 2009 at 03:25

Merlin5 said:
Thanks. Ah, I didn't know DDR meant that. So if for instance I had bought the faster DDR2 PC2 8500, it would have said 'Max Bandwidth PC2-8500 (533MHz)', but you'd just double that up to 1066. Is that about right?

In task manager, it's telling me Physical memory (K)3406252 and Available memory (K) 2803000, that's about 3.4GB and 2.8GB so that sounds like what you said.

Just to confuse you, 32 bit versions of windows can see that you have greater than 3GB of RAM and will inform you of this in the System Properties - but it can't actually address to those areas which fall outside of the 3GB boundary (incidentally its 2^32 but a certain amount of address space is reserved)

Merlin5 · 1 Sep 2009 at 04:28

Yeah, it makes sense. System info has been showing me that it sees all 4GB, but yeah, it can't make use of it all. Interesting though how system info says 2.57GB available memory, and task manager is constantly giving a higher figure of 2.7 to 2.8. So I'll assume I actually have nearer to 3GB than system info says because it makes me feel better until I buy and install windows 7 64 bit

Anyway, this pc I just built is lightning fast, I'm more than happy with the amount of memory it can use for now.

EDIT: Well, it gets more interesting for me. I just did an old 3D mark 03 and look at the memory figure on the left, that's mine. So I DO apparently have over 3GB. That's well good.

http://img268.imageshack.us/img268/6713/screenshot001hbe.jpg

Merlin5 · 1 Sep 2009 at 16:10

This ram is specced at 4-4-4-12 timings. This screenshot I took shows various timings, but in my bios it's auto set to 5-5-5-12. Shall I reduce it 4-4-4-12? If I do, do I need to change any other things like voltages?

Merlin5 · 4 Sep 2009 at 01:02

Oh. it was easy, I just enabled EPP mode and EPP voltage and it did it all for me.

CPU-Z is now showing me the specced 4-4-4-12 and 2.1v voltage, everything seems stable, and my cpu temperature hasn't gone up.

dustofnations · 4 Sep 2009 at 02:24

Merlin5 said:
Oh. it was easy, I just enabled EPP mode and EPP voltage and it did it all for me.
CPU-Z is now showing me the specced 4-4-4-12 and 2.1v voltage, everything seems stable, and my cpu temperature hasn't gone up.

I found that when I left the BIOS to do everything for me it tended to use a way higher CPU voltage than needed (raising the temps significantly), could be different in your case of course.

Merlin5 · 4 Sep 2009 at 03:00

dustofnations said:
I found that when I left the BIOS to do everything for me it tended to use a way higher CPU voltage than needed (raising the temps significantly), could be different in your case of course.

Nope, my cpu voltage is at 1.344 (actually says 1.35 in bios) as it was before I set EPP. I'm curious how EPP sets it to 2.1v, because when I took a look at the increments in the DRAM manual voltage settings in bios, there was 2.0v and then 2.2v, but no 2.1v.

dustofnations · 4 Sep 2009 at 03:15

Merlin5 said:
Nope, my cpu voltage is at 1.344 (actually says 1.35 in bios) as it was before I set EPP. I'm curious how EPP sets it to 2.1v, because when I took a look at the increments in the DRAM manual voltage settings in bios, there was 2.0v and then 2.2v, but no 2.1v.

<snip>

Ah I just realised I mistook EPP for ET (EasyTune/Gigabyte auto-overclocker settings in BIOS) when scanning too quickly and looking at the pics, ignore the CPU voltage comment from earlier as irrelevant.. I also noticed a couple of discrepancies between EasyTune and the BIOS (with settings possible in easytune that were not available in the BIOS). Suppose its just a quirk..

Merlin5 · 4 Sep 2009 at 03:24

Yeah, I'm not sure how good easytune really is. For instance, when I temporarily disabled smart fan via easytune, I could hear the fan spinning up and making more noise but didn't see any temperature change readout in easytune. Perhaps I might have seen a different reading in bios. It also doesn't show what my ram timings are or have changed to, it just shows those timing tables now the same as in the earlier screenshot I posted, whereas in cpu-z, it shows the actual change in timings.