OCing x2 3800+, disappointed in my results, need some help

Leros

Lifer
Jul 11, 2004
21,867
7
81
Other than overclocking an old P3 (1000Mhz to 1250Mhz), I'm a real noob to this. I got some DDR 500 RAM, so I was really hoping to get my FSB up to 250 Mhz so I could run without a divider.

I went through the "Quick and Dirty A64 Clocking Guide".

I was able to get my HTT up to 355 without any errors, I could have gone further, but I saw no need to waste my time trying.

Next, I raised the stepping on the CPU. My goal was 250Mhz. With 1.5v, I was able to get there, but Prime would fail after about 30 minutes. Not very stable. This is my goal, but I am afraid to raise the CPU voltage. Should I?

I dropped down to 240Mhz and dropped the voltage to 1.4v. I ran Prime on both cores overnight. One core failed after 8 hours. The other instance of Prime crashed pretty early on (about 10 tests) and I got the Windows error reporting box.

Now, I am a bit confused about the whole memory speed. My old Soltek board used to let me key in any frequency I wanted (up to 300). The DFI Ultra-D only lets me select a few freqencies at or below 200. There is also an auto setting. With Auto, the memory runs at 250Mhz, which is stock (DDR 500).
Two questions about this:

1) When I had my FSB at 240, my memory was still at 250. How does that work? I understand having RAM running slower than your FSB, but not faster.

2) On my P3 board and my Soltek 939, I can set the memory to any speed (for instance, I could set it to 240Mhz and be running a 1:1 ratio). Why can't my DFI do this? I assume I'm missing some crucial concept here.


So, right now I stand at 240Mhz x 10 = 2400Mhz overclock that is not very stable. Ive been surfing the web for an hour with no problems, but it failed Prime miserably. What should I be doing?

Should I increase CPU voltage? If so, how far? What is safe? I heard that the x2 series does not take voltage well.

Should I accept my 2400Mhz clocking? My goal was 2500Mhz and I feel that is somehow attainable.

Rig Specs:
DFI Lanparty Ultra-D
A64 x2 3800+
2 x 1GB G.Skill DDR 500 Extreme Series
Antec NeoHE 500w
SI-120 w/ 120mm Panaflo
(the rest shouldnt matter)

 

JustAnAverageGuy

Diamond Member
Aug 1, 2003
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Originally posted by: JToxic
I have LDT set to auto. Should I be setting this manually?

Worth a try ;)

I'm not familiar with the BIOS of that particular DFI board though, so I couldn't tell you where to find it.
 

Leros

Lifer
Jul 11, 2004
21,867
7
81
Does LDT have a perfomance impact? As in, is it better for it to be high or low, or does it not matter?
 

Leros

Lifer
Jul 11, 2004
21,867
7
81
I set my RAM and FSB to 250Mhz. I have my LDT at 4x. I set the CPU voltage to 1.5v (CPU-Z says 1.456v).

Both cores failed prime in under a minute. Is there anythign else I can do?
 

JustAnAverageGuy

Diamond Member
Aug 1, 2003
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0
76
LDT does not affect performance.

Memory voltage set to 2.8V
Memory timings 3-4-4-8 ;) 2T command rate if you want to. Just eliminating variables.

 

Shimmishim

Elite Member
Feb 19, 2001
7,504
0
76
Now, I am a bit confused about the whole memory speed. My old Soltek board used to let me key in any frequency I wanted (up to 300). The DFI Ultra-D only lets me select a few freqencies at or below 200. There is also an auto setting. With Auto, the memory runs at 250Mhz, which is stock (DDR 500).

You are looking at the memory dividers

you probably saw something like

200
180
166
150
133

etc..

these are not memory frequencies. they are your dividers.

change your LDT to 3x.

change your FSB Bus frequency to 250

Under DRAM Configuration:
make sure your divider setting is at 200
change all memory settings to AUTO

I say leave at 200 or 1:1 since you have ddr500 ram.

then change CPU VID control to 1.5
CPU VID Special to AUTO
Change DRAM voltage Control to 2.8

try that.
 

Leros

Lifer
Jul 11, 2004
21,867
7
81
Shimmishim,

I tried your suggestion and Prime failed in under a minute.

Any other suggestions?

 

Wentelteefje

Golden Member
Dec 6, 2005
1,380
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0
Going over 1.5V isn't deadly or so... Do you have a decent HSF, or is it the stock one? Try upping the voltage slowly... DFI must have a plethora of voltage options... BTW did you try to raise the chipset voltage?
 

Leros

Lifer
Jul 11, 2004
21,867
7
81
Originally posted by: Wentelteefje
Going over 1.5V isn't deadly or so... Do you have a decent HSF, or is it the stock one? Try upping the voltage slowly... DFI must have a plethora of voltage options... BTW did you try to raise the chipset voltage?

I have the SI-120.

1.5v at 250Mhz made me idle at about 45C.

I have no raised chipset voltage. Should I be doing this?
 

richardrds

Senior member
Dec 7, 2004
303
0
0
Try setting your mem divider to 166 or 133, I know you said you have ddr 500 ram and it should be able to run at up to 250Mhz HTT at 1:1, but run a few tests with the ram divider set, this will eliminate ram as your issue.
 

Wentelteefje

Golden Member
Dec 6, 2005
1,380
0
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Originally posted by: JToxic
Originally posted by: Wentelteefje
Going over 1.5V isn't deadly or so... Do you have a decent HSF, or is it the stock one? Try upping the voltage slowly... DFI must have a plethora of voltage options... BTW did you try to raise the chipset voltage?

I have the SI-120.

1.5v at 250Mhz made me idle at about 45C.

I have no raised chipset voltage. Should I be doing this?
It would eliminate the chipset being the limiting factor... It's not uncommon to raise its voltage while overclocking...

richardrds's advice is right as well... Although it seems weird that RAM would not be able to run at its nominal speed, it's a possibility as well... The G.Skills look good actually...
 

Leros

Lifer
Jul 11, 2004
21,867
7
81
Im certainly surprised.

I ran Prime successfully for an hour.

166 memery dividor
250 FSB
x3 LDT
x10 multi
1.5v CPU VID
1.2v LDT voltage (default)
1.5v chipset (default)
2.8v DRAM

I dont get it. Does this mean my memory is bad or could it be something else?
 

Leros

Lifer
Jul 11, 2004
21,867
7
81
Also, does this mean that my CPU is capable of running 2500 Mhz? And that the problem lies elsewhere?
 

Leros

Lifer
Jul 11, 2004
21,867
7
81
I ran memtest with my RAM at 250Mhz and got a few errors. Crap.

Guess, I gotta get new RAM.
 

Shimmishim

Elite Member
Feb 19, 2001
7,504
0
76
Originally posted by: JToxic
I ran memtest with my RAM at 250Mhz and got a few errors. Crap.

Guess, I gotta get new RAM.

have you messed with the ram timings yet?

or is everything on auto?
 

Leros

Lifer
Jul 11, 2004
21,867
7
81
Originally posted by: Shimmishim
Originally posted by: JToxic
I ran memtest with my RAM at 250Mhz and got a few errors. Crap.

Guess, I gotta get new RAM.

have you messed with the ram timings yet?

or is everything on auto?

Its all on auto. I'm only 75% of the way through MemTest and there have been 6 errors. On both sticks.
 

Leros

Lifer
Jul 11, 2004
21,867
7
81
I was reading the review for the RAM on newegg to see if there were any complains.

The first review said this:

Cons: There is a batch of this RAM on the market that runs witht he wrong default timings. They are beening shipped with 3-3-3-7 when they should be 3-4-4-8


Other Thoughts: If after installing these you should go into your BIOS and check/change the timings. Then these babies will do their rated DDR500. I see that most people using these are using DFI mobo's and there isn't much on the web that i could find that said whether or not these will worn on ASUS mobo's but I took the risk anyway and they work GREAT. I haven't OC'd them yet but it's running my 3700+ SD @ 250x12 @ 2.75ghz. BTW my mobo is the A8N SLi Deluxe.

Once memtest finishes, I'll try manually setting it to those settings.


 

richardrds

Senior member
Dec 7, 2004
303
0
0
Glad you took my advice and have it narrowed down to your RAM. But before you give up on the ram you could try to relax its timings a little bit. Sometimes the advertised timings on RAM are for P4 installations, and you need to relax them a little for A64 (ie... if your rams advertised CAS latency is 2 try running it at 2.5, or if 2.5 try running it at 3.)

Also with the archetecture of the A64 chips you could just run cheap PC3200 Value ram and use the 166 divider. It will only cause a few % hit on perofrmance, maybe max of 2 to 4% depending on the app or game that is running. See Zebo's great thread discussing this:

http://forums.anandtech.com/messageview...atid=28&threadid=1475190&enterthread=y
 

Leros

Lifer
Jul 11, 2004
21,867
7
81
Originally posted by: richardrds
Glad you took my advice and have it narrowed down to your RAM. But before you give up on the ram you could try to relax its timings a little bit. Sometimes the advertised timings on RAM are for P4 installations, and you need to relax them a little for A64 (ie... if your rams advertised CAS latency is 2 try running it at 2.5, or if 2.5 try running it at 3.)

Also with the archetecture of the A64 chips you could just run cheap PC3200 Value ram and use the 166 divider. It will only cause a few % hit on perofrmance, maybe max of 2 to 4% depending on the app or game that is running. See Zebo's great thread discussing this:

http://forums.anandtech.com/messageview...atid=28&threadid=1475190&enterthread=y

See my post above about the ram timings. It turns out that mine are running the wrong timings. Once I figure out how to read RAM timings, I will change them.

*goes to search RAM timings*

 

Leros

Lifer
Jul 11, 2004
21,867
7
81
Once I fixed the timings, it passed Memtest. I have yet to overclock and run Prime. I'll start that in 30 minutes.
 

Leros

Lifer
Jul 11, 2004
21,867
7
81
I was able to run Prime95 on both cores for 14 hours without any errors. Everything seems to be doing pretty good. Thanks guys.