DRAM Frequency - how do i change it?

When I installed the Sempron 3400+ processor I currently have in my pc I also installed 512 MB of new DDR-SDRAM. Mindful that the Sempron has a 200 MHz FSB, I installed a Kingston PC3200 (200 MHz) memory module. More recently I installed a second (Transcend) PC3200 module, making 1024 MB in total. Their latencies differ but I don't understand the relevance of this - if any. I saw no need to match them exactly because the Sempron doesn't have dual-channel memory.

But I've noticed that in my BIOS's boot screen there are two columns, both headed "Default/Current ", and that against "DRAM" under the first column 400 MHz is given as "Default" and only 333MHz as "Current ". (under the other column "auto/auto" appears). I don't know what to make of this. Surely, "Current" ought to be 400 MHz - otherwise I've wasted my money buying 200 MHz RAM modules?

I've searched my BIOS's Setup for some way in which I can step-up the DRAM frequency. The only place I've found where any memory settings at all are changeable is in a page headed "Frequency/Voltage Control ". Here, as well as being able to change the FSB multiplier (currently set at 10) there's an entry called "Max Memclock" which "places an artificial memory clock limit on the system..." In other words, it does the opposite of what I want - and the highest it can be set is 333MHz (Increasing the multiplier has no effect on this whatever).

I can't make any sense of this at all. An enquiry to AOpen's Tech Support hasn't even been favoured with an answer. Is anyone able to instruct me, please, about what is going on here? It's beginning to bother me.


AOpen AK86-L motherboard
VIA K8T800-VT8237 chipset
Sempron 3400+ 2.0GHz
AGP card: Asus V9520 'Video Suite'; TV out
GPU: GeForce FX5200 128MB DDR
LG Flatron L194WT digital monitor
1024 MB DDR memory
Samsung SATA 160GB HDD
Samsung SATA 230GB HDD
LG 4020B IDE multi-drive
Creative Audigy2 soundcard
TechnoTrend TV stick USB DVB-T card
O/s: XP Home SP2

 

Hello kosketus,
Looking at the motherboard manual, it should be controlled by the setting "Load Turbo Defaults ". If the system is unstable using Turbo, you will need to go back to Setup defaults and say try running Turbo with each RAM module separately.

It will change other speeds/frequencies, not just the FSB.

There are some specific placement locations for the RAM modules, page 33.

Matt

 

Hi mattman

How come you're so familiar with this mobo's handbook (more familiar than I am myself) - is it that you have the exact same mobo, or is it just sheer expertise ? Either way, I'm impressed.

I loaded 'Turbo Defaults', then made a couple of tweaks to restore some previous settings here and there - nothing major. The 'Max Memclock' had re-set itself to 'Auto' instead of 333 MHz. However, having saved and exited I found that nothing had changed on the boot screen - it still shows "Current" DRAM at 333MHz.

Any further thoughts, or is this the end of the road?

 

Hi, kosketus.

I supect mattman downloaded the manual via http://global.aopen.com/download.aspx using your motherboard specs. He's pretty darn good with hardware in general too!

 

Go into your BIOS and select the page titled Advanced BIOS settings or something closely similar. Even though they may be grayed out due to auto memory configuration, what are the numbers for each of the following memory settings?
CAS
TRCD (RAS to CAS delay)
TRP (RAS Precharge)
TRAS (Active to Precharge)



edit: Put an r in grayed

 

Just a note, when you exited the BIOS settings, did you "Save the changes "? If it reverted to original settings I would expect that it should have shown information that it needed to do so.

Be careful about Max Memclock, I did not read about it. Try the Turbo setting first. "Max Memclock" sounds like it will push the RAM to the limit. A rule I use...only make one change to the BIOS settings at a time, if there are any apparent problems, you will know which one caused them.
_________________________________________________________________
Shhh!! "AOpen AK86-L manual" in a websearch, although the Aopen website is quite easy to navigate compared to a lot of the others. I try a quick websearch first though.

Get those details for Rockster2U, I think there will be a lot gain from his analysis.

Matt

 

Yup

No, it restricts RAM to a specific frequency, which is either selectable from among three choices or can be set to 'Auto' (whatever that means). None of the choices it's offering is as high as 400 Mhz.

If it is in fact Max Memclock which is limiting my BIOS to a current DRAM frequency of 333MHz, I guess that what I would need to be able to do is to stop Max Memclock from having this effect - ie to deactivate it. All 'Turbo Defaults' did was to set it to 'Auto' - which had zero effect.

But nowhere in the BIOS can I see any way of over-riding or disabling Max Memclock.

 

Hi Rockster

They're not gayed (sorry, grayed)-out they're all set to 'Auto' - simply because had I chosen to set them manually instead I wouldn't have had a clue what values to set them to

CAS:- 2.0, 2.5, 3.0
TRCD:- 2, 3, 4, 5, 6, 7
TRP:- (ditto)
TRAS:- 5, 6, 7, 8, 9, 10, 11

(I can't see any way to add an attachment. If I could, I'd attach screen dumps I've taken of CPU-Z outputs - SPD tab - for each of my RAM modules. Is there some way to do this?)

EDIT

I remember now that I already asked this question before, and that it was answered. I just forgot - sorry!

 

Remove the Transcend memory module and see if the Bios reverts to 200MHz for the Kingston module. That Transcend module may actually be PC2700 and the memory is reverting to the lower rating. It wouldn't be the first time that that a memory module is labeled incorrectly. I have also found that Kingston doesn't like to be mixed with some other brands.

 

Hi Whiskeyman

(Irish or Bourbon?)

But the CPU-Z SPA readout for the Transcend module (which I haven't yet been able to post - see above) says that its maximum bandwidth is PC3200 200 MHz. Does this convince you. or might it still be PC2700 in spite of this?

But I'll try out your suggestion anyway to test your second suggestion.

EDIT

I've now posted screen dumps of the CPU-Z SPA readouts (see below)

 

Here's the URL

http://s234.photobucket.com/albums/ee113/kosketus/?action=view&current=spd_mem.jpg

 

I believe the mismatched brands are causing the issue. I wonder if it is reverting to 166MHz due to the 2.5 CAS latency matching at that speed.

 

Unfortunately, the numbers you have supplied is the universe of all possible numbers. What we need to know is what are your machine's current timings. There's more than one way to skin a cat so we'll get to that in the last paragraph.

Generally speaking, I'd agree with Whiskeyman's prognosis as the "mismatch" being the most likely culprit and his observation that some memory suppliers categorize their products based upon the highest achievable speed - translation -> what may be decent PC2700 is a poor excuse for PC3200. However, we can probably get a little more specific with your help.

Download and install Everest (version 2.20 if possible). Then on the Motherboard Tab of Everest, go to the SPD module and look at the ratings for each of your memory modules. Then give us the memory timings for each module at both 200MHz and at 166MHz. This will be a series of 4 numbers with dashes between them. (corresponding to my earlier post) Also note in the upper section of listings - what is the memory speed shown for each module?

 

Here's the last free version of Everest (v2.20).

http://www.majorgeeks.com/download4181.html

 

DIMM1: Kingston K
Speed PC3200 (200 MHz)
Timings:-
200 MHz 3.0-3-3-8
166 Mhz 2.5-3-3-7

DIMM2: Transcend
Speed PC3200 (200 MHz)
Timings:-
200 MHz 2.5-3-3-8
166 MHz 2.0-3-3-7

 

First, the disclaimer - this is going to be a little bit like "Pin The Tail on the Donkey ". We may get lucky and we might not, but it's worth taking a stab at it. Should you wind up unbootable, you'll have to pull your CMOS battery for 20-30 minutes to reset CMOS as I don't think this board has a CMOS jumper. If this happens, please note that you will then (after clearing CMOS) need to reset everything in your BIOS (date, drives, boot order, memory & etc.).

Here we go .......... head into your BIOS and on the Advanced tab, select manual for memory and then set the following.

Speed or frequency - 200MHz
CAS: 3.0
TRCD: 4
TRP: 3
TRAS: 8

Now, save your settings and exit out (F-10). Let us know if that tail wound up between the Donkey's cheeks or if we pinned it on the wrong wall. If successful, you can also try 3-3-3-8 as a potentially better alternative. If unsuccessful, I don't think you have too many other options which are going to get both modules to 400MHz (200x2) when used together.

 

It has, in fact - though it's a PITA to get at....

Well, it was certainly on target in terms of the donkey's anatomy. Unfortunately, however, changing to these timings (either of them) hasn't changed the DRAM frequency as reported by the boot screen: it still shows 333 MHz as 'current' frequency

I think my next step has to be to open-up the case, remove the Transcend module and see what effect that has - if any.

 

Well, I did that and - guess what - the boot screen now shows 400 MHz as "current" DRAM frequency. So the hypothesis that the problem arose from my having mixed modules from different manufacturers would appear to be spot-on. I have yet to try swapping the Transcend for the Kingston, but I fully expect that that will have the same result.

If so, it presumably means that I can either have 1 GB of RAM running at 333 MHz or 512 MB running at 400 MHz - a no-brainer really since I imagine that twice the memory capacity must be worth more in performance terms than half as much running 20% faster. (I do a fair amount of video processing). Anyway, I've paid for the additional 512 MB so might as well use it.

This has been a cautionary tale As I mentioned at the start, I took it that to match RAM modules would (on a tight budget) be an unnecessary luxury when not using dual-channel memory - so long as I didn't buy unbranded junk. I now know that this was a mistake. But I don't remember ever having previously come across any advice to that effect. Doubtless a close reading of what the manufacturers' websites say would have revealed this, but wouldn't I have been inclined to take their advice NOT to use a competitor's products with a pinch of salt...?

EDIT

Just to confirm that, as expected, swapping the Transcend for the Kingston had exactly the same effect - 400 MHz RAM frequency. BTW, in the process the BIOS itself set all the memory timings back to 'Auto' - presumably these are the default settings though it's not clear to me why it should revert to the defaults of its own volition.

 

A most valuable lesson re: saving a few bucks only to discover that something else has been compromised. The last ditch effort that you may want to consider is setting your timings manually and including a T2 timing (if it was at T1) but I doubt this is going to resolve things either.

You may want to do a little experimenting re: the 512 vs 1024 also. Although I am running 2 gigs in each of my desktops and my newest laptop, my file server runs better with 512MB of OCZ than with 1024 of Corsair XMS. Oddly enough, the Corsair is 2-2-2-5 and the OCZ is 2-3-2-5 - go figure.