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DDR2 800 running at 533. What gives?

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September 12, 2006 3:11:36 PM

I have a P5B Deluxe MB with Core 2 Duo e6600 and 2GB Corsair XMS2 RAM.

When I run 3Dmark06 it says my RAM is at 533Mhz. If I go into BIOS and change the frequency to 800Mhz, my system crashes and won't reboot... causing me to reset the CMOS.

How do I fix this problem?

More about : ddr2 800 running 533

September 12, 2006 3:40:13 PM

If there is an option for 'Auto' use that.
September 12, 2006 3:57:42 PM

The native FSB for the Conroe CPU's is 266MHz x4 which is effectivly 1066MHz FSB. So your DDR RAM will run at 266MHz x2 which equals a 533MHz DDR bus for the memory. This is perfectly normal. When you are setting the RAM to 800MHz you are over-clocking your FSB to 400MHz (or 800MHz DDR) which is well beyond the stock setting. It is possible with proper cooling and some serious tweaking to actaully reach that speed.... but you sound like a begginner (no offense) so I wouldn't recommend that at this time. Just rest assured that the 533MHz memory speed is normal for your processor and will work just fine for you... unless you really want to get into serious OC'ing. :D 
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September 12, 2006 4:10:20 PM

No offense taken, I'm a n00bie in the OCing world. So far I've built probably 24 PC's so far for friends, family, coworkers, and of course myself.

I've never really found a need to Overclock until I read that article on the D805 running at 4.1!!! I got it running stable at 3.65 Ghz on air cooling which was impressive enough... I guess the ambient temp in my room was too high and the thing would crash after 1-15 minutes of load...

Anyway, that got me into the whole OCing bug.

So essentially buying DDR2 800 was a waste, and effectively I coule use DDR2 533 and get the same performance results as long as the timings match up?
September 12, 2006 4:14:16 PM

Quote:
The native FSB for the Conroe CPU's is 266MHz x4 which is effectivly 1066MHz FSB. So your DDR RAM will run at 266MHz x2 which equals a 533MHz DDR bus for the memory. This is perfectly normal. When you are setting the RAM to 800MHz you are over-clocking your FSB to 400MHz (or 800MHz DDR) which is well beyond the stock setting. It is possible with proper cooling and some serious tweaking to actaully reach that speed.... but you sound like a begginner (no offense) so I wouldn't recommend that at this time. Just rest assured that the 533MHz memory speed is normal for your processor and will work just fine for you... unless you really want to get into serious OC'ing. :D 



That's strange, because I have the E6600 and Intel 975XBX mobo, and I have XMS2-667 ram and it is running at 667MHz. By your explanation, it should also be running at 533MHz.

This brings up another question. Intel says that the 975XBX mobo supports 533MHz and 667MHz ram. However, when I check with Corsair, they say their 800MHz and 1066MHz ram will also run in that mobo.
But if they don't run at their rated speeds why spend the extra money on them.

hball
September 12, 2006 4:29:30 PM

Unless your BIOS is limited, you should be able to change the memory bus speed to DDR2-800 (=400MHz) while leaving the FSB at 266MHz (1066MHz effective data rate). Perhaps there are additional settings controlling the ratio between FSB and memory bus that you need to change to accomplish your goal.
September 12, 2006 4:43:53 PM

Quote:
The native FSB for the Conroe CPU's is 266MHz x4 which is effectivly 1066MHz FSB. So your DDR RAM will run at 266MHz x2 which equals a 533MHz DDR bus for the memory. This is perfectly normal. When you are setting the RAM to 800MHz you are over-clocking your FSB to 400MHz (or 800MHz DDR) which is well beyond the stock setting. It is possible with proper cooling and some serious tweaking to actaully reach that speed.... but you sound like a begginner (no offense) so I wouldn't recommend that at this time. Just rest assured that the 533MHz memory speed is normal for your processor and will work just fine for you... unless you really want to get into serious OC'ing. :D 



That's strange, because I have the E6600 and Intel 975XBX mobo, and I have XMS2-667 ram and it is running at 667MHz. By your explanation, it should also be running at 533MHz.

This brings up another question. Intel says that the 975XBX mobo supports 533MHz and 667MHz ram. However, when I check with Corsair, they say their 800MHz and 1066MHz ram will also run in that mobo.
But if they don't run at their rated speeds why spend the extra money on them.

hball

All of you bring up excellent points.

I think it's really a screwed-up thing what the CPU and memory makers are doing.

Remember, back in the day, how easy it was to buy DDR memory and any given CPU? Remember when that CPU and memory ran at its advertised speed WITHOUT having to first check out the speed of the CPU and chipset and RAM, and do all sorts of mathematical bullshit calculations to make sure it would run at the speeds you wanted it to?

I think that if the guy bought some 800MHz RAM, then it should run at that speed. Memory guys are in the wrong because they should warn users that it might run slower than advertised on select CPUs.

The CPU guys are also in the wrong for making odd-numbered clock speeds that they know won't work (at the RAMs top speed), with certain memory modules.

I dunno...I think the whole industry could really help things by simplifying their product lines. For instance, the CPU guys would make say 4 types of processor: an extremely high-end, high-end, middle, and low-end types. Each processor type would outperform the levels lower than it, so no more will we see, say, a 3800+ being the equal of a 4200+ or 4600+ (that isn't really an accurate statement, but I think ya'll know what I am talking about). Clock speed differences would also in increments that take advantage of DDR2s speeds (so no more will we see what the original poster encountered: a CPU mismatched to higher-speed RAM).

Let's burn it all down.
September 12, 2006 5:28:04 PM

If your system is crashing at 800, use CPU-Z to make sure the latency and voltage is correct.
My ASUS mobo (P5n32 SE) did not detect it correctly, which according to Corsair test is expected.

I changed the latency to the Corsair indicated timer and manually set the voltage to the correct Corsair value of 1.9v.

Prior to that setting the RAM to dual 800 @5-5-5-15 @voltage at auto would cost the system to lock up.

I have it set now to 5-5-5-12@ 1.9v.
September 12, 2006 6:24:29 PM

I wouldn't call your DDR2 800 purchase a waste pixel. Like I said before, it certainly can reach those speeds... it just doesn't at stock of course. Also, when OC'ing you don't just jump from stock to top speed right away. You have to go up in small increments and adjust voltages and such as you go until you find your max stable OC. With that mobo and CPU you should be able to reach those speeds. You may need to drop your CPU multiplier down too, but that's where to trial and error tweaking comes in. Read the OC forums and see what other's here have done. You'll see that you can get some pretty incredible results on air cooling with the E6600 you bought! :D 
September 12, 2006 11:03:41 PM

You are incorrect, setting the RAM to 400MHz clock, 800MHz effective, should have no effect on the FSB speed of 266MHz (1066MHz effective) on the P5B deluxe (or any other recent mobo that I can imagine for that matter). As an example, the clock on my RAM is 400MHz (800 effective) while my FSB is 200MHz (800 effective).

However, your RAM may be rated for a higher voltage than the 1.8v, and wont perform at its rated speed with only 1.8v.

Try setting your VDIMM to 2.1v.

Assuming it is This Coresair TWIN2X2048-6400C4PRO then it is rated at 2.1v
September 12, 2006 11:26:22 PM

The original poster hasn't given us enough details about what *exactly* he did for us to figure out whether it's an error in BIOS settings or the RAM not runnig at DDR2-800 at 1.8V.
September 13, 2006 2:16:17 AM

I'm sorry to hijack this post a little, but I have a similar problem. I just built my first PC and am new to this. Slowly but surely I'm going through all the diagnostics to try and optimize my system. I think I've just unconvered a problem with the memory.

I got 2GB of the OCZ DDR2 800 Rev 2, CAS 4
http://www.newegg.com/Product/Product.asp?Item=N82E1682...

I ran CPU-Z as someone here suggested. I uploaded images of the output:

http://img179.imageshack.us/img179/2246/memsnr9.jpg

http://img179.imageshack.us/img179/942/mems1yd0.jpg

It appears that my memory is 267 Mhz at CAS 5. I'm new to this, but I paid for DDR2 800 Mhz at CAS 4!!! Could someone please take a look, and advise me where it should be at stock. I'll get to OC'ing another day. Thanks guys!

FishBoi

PS. I also have a Conroe E6600, Asus P5W DH Deluxe mobo, and MSI x1900xt v-card, Seagate Barracuda 320GB. THANKS!
September 13, 2006 6:59:18 AM

Quote:
...
It appears that my memory is 267 Mhz at CAS 5. I'm new to this, but I paid for DDR2 800 Mhz at CAS 4!!! ...

That's just the "auto" setting. You'll need to look up the voltage the manufacturer specifies to get the CAS 4 timing, then manually set the DIMM voltage, *then* the timings in the BIOS.
Since DDR2 technology is so new and all the kinks aren't quite worked out yet, manufacturers have more recently been programming their SPD settings (the "auto" settings) very conservatively, so the RAM will at least run on just about any MB. Corsair/nVidia have taken the next step by using otherwise-unused SPD space to program in additional, more-agressive timings and voltages that can be used automatically by MBs that are compatible with this new timing info standard (EPP).
September 13, 2006 2:14:28 PM

Ok cool. Here is a link to the mfg.'s website:
http://www.ocztechnology.com/products/memory/ocz_ddr2_p...

Do you perhaps know exactly where I have to set that in the Asus P5W DH website. I'm not sure where to find it there (maybe power management if I can remember right?)

Also, when you say set the timings, how exactly do I do that? From that link, it says CL 4-4-4-15 (CAS-TRCD-TRP-TRAS) for the timings. If I understand that correctly, I have to go into the BIOS and type 4, 4, 4, and 15 into certain cell inputs right? How do I know which ones go where?

Thanks. I feel like such a noob.
September 13, 2006 2:15:45 PM

PS. The RAM didnt come with a manual, and I cant see it on the manufacturer's site (about the voltage I mean). How do I set that and find out how much I need to set it to? Thanks!
September 13, 2006 2:26:47 PM

If anyone has a screen shot of the BIOS screen that I need to tweak, I would really apprecaite it. THANKS!
September 13, 2006 2:30:53 PM

Sorry and one last noooob question: What is the optimal memory settings for this type of system? I hear that increasing your memory speeds could actually result in decrease performance. Should I set the timings to 4-4-4, and set the RAM to 800Mhz? Will this give me optimal performance???? Or should it be lower (something about ratios)? Thanks guys!
September 13, 2006 2:36:25 PM

Another stupid question - if I change the timings and for some reason it's incorrect, so I only figure that out when I restart the PC. For example, I need to exit the BIOS and save the settings, then when I reboot, it wont POST right? Then can I just get back into the BIOS and rest the settings.

Anyway to auto detect your best settings. Seems like such a pain if you're trying to decrease your voltage as much as you can, while still maintaining the recommended timings.
September 13, 2006 3:40:10 PM

Set it your RAM to 800. Set the latency to 4-4-4-12 @ 2T and 2.1v.

If you still having problems then downgrade to 5-5-5-18.

If it does not POST, just reset it again.

Also, some ASUS mobo BIOS must be clear upon initial installation (check the manual how to do it. It involves a jumper switch).
September 13, 2006 4:29:16 PM

OK great. Thanks man! Appreciate it. I will hit it up tonight.
September 13, 2006 4:33:11 PM

Sorry, one last question. When you said 2T, what did you mean. Where do I set this, and what is it for?

The other settings make sense - I will just have to find the mem voltage setting in the BIOS.
September 13, 2006 4:58:59 PM

1t or 2t are 'Command Rates'

If it is not there, then don't worry about it or leave it at auto.
September 13, 2006 6:35:33 PM

Ok thanks guys.
!