How bad is it? (Update: X2 stable at 2750MHz @1.4625)

[lopri]

/Update: My X2 4800+ is Prime95 stable for 10+ hours @ 2750MHz (VCore 1.4625)

Now my options are..

1. CPU: 10.5 x 261 = 2741, RAM: DDR333 = 211MHz
2. CPU: 11 x 250 = 2750, RAM: DDR333 = 194MHz

I did a quick Sandra test, and the CPU results are almost the same from both settings, but there are quite a bit difference between memory bandwidth. (option 1 scoring nearly 500MB better)

So my question is, is there anything "inherently" bad about runing half-multi? Because in theory, I don't see any. (Well, at least in my case where I can't choose anything between DDR333/DDR400 in BIOS)

Also, Do I need to increase the chipset voltage after HTT 250? (from default 1.5V to 1.6V)

/End Update




My current setup is X2 4800+ with A8N-SLI Premium. After some testing, I've found my limits but the narrowing down the best choice is quite difficult. Most limiting factor here is my RAM. I have 2 sticks of 1G, and no matter what I do they won't go past 220MHz. (Thankfully at good timing, 2-3-2-5-1T)

So, here is what I have:

CPU (Max): 2700MHz @1.425V
RAM (Max): 220MHz @2.75V (2-3-2-5-1T)

And, here is what I can do:

1. HTT 220 (Multi x12): CPU 2640MHz (220x12), Memory 220MHz (1:1 or DDR400)
2. HTT 246 (Multi x11): CPU 2706MHz (246x11), Memory 194MHz (5:6 or DDR333)
3. HTT 257 (Multi x10.5): CPU 2699MHz (257x10.5), Memory 207MHz (5:6 or DDR333)

The biggiest limiting factor is that my Memory. It won't go any further than 220MHz, and my board doesn't support any other useful divider. So I can only choose DDR400 or DDR333. (nothing in-between)

The closest configuration to both CPU/RAM max is with the CPU multi 10.5 - I get 2.7GHz/207MHz. (Option 3) Then again, I believe it's not recommended to use non-integer multi.

If I want to keep 1:1 setting I lose about 60MHz on the CPU. (Option 1)
If I want to keep the Max CPU then I need to use the divider AND lose 26MHz on the memory. (Option 2)

One thing to keep in mind is that my RAM wouldn't go any higher even with loser timings. I tried many combinations but it eventually fails in Prime95. So I gave up messing with it.

What do I do?? CPU speed is still the king, even though I have to use the divider and lose significant amount of speed on RAM?

Any input would be appreciated.

lop

 

[phaxmohdem]

Unless you're trying to set some sort of speed record, I would just stick to option 3 I don't think the .5 multi will hurt you or your chip, and I've never heard that its bad to do so either.

2.7GHz dual core AMD is FAST anyway you look at it. What is your motivation to go higher? IF you get too pissed off at it I'm always open to donations

What kind of RAM are you running BTW??

 

[bjc112]

I would go with Option 2.

With AMD speed always wins.

What are the timings on the memory at the three settings?

@ 6mhz below stock memory speed, you should also be able to tighten up the timings to their maximum.

 

[lopri]

Phax:
2.7GHz dual core AMD is FAST.. yeah.. tell me about it. Especially for someone who used the P4 before this setup. I just wish if I had made the switch earlier. Anyway, I'm not trying to go faster but want to make the most out of my hardware.

I'm using 2X1G OCZ Titanium. Great ram, I'd recommned it to anyone but the hardcore overclocker. Now if only these sticks could do 225MHz.. (That's just 5MHz more!) I'd be the happiest person in the world.

bjc112:
I'm running the RAMs at 2-3-2-5-1T right now. Maybe with 194MHz I could run them at 2-2-2-5-1T ? I don't know why I haven't thought about. Thanks for enlightening me! I will definitely try it.

lop

 

[Shimmishim]

there are better 2 x 1 gig sets... i can't remember what but i know there are some that can get up to 240 to 250

 

[lopri]

Shimmishim:
Yes I know but I'm not intending to buy another pair of RAM. Even so, those 1G sticks will probably run at loose timing to achieve higher MHz anyway.

 

[lopri]

Well, It turns out my RAM won't do 2-2-2-5 at even lower speed..

So.. Would there be any penalty running the CPU at 10.5 multiplier? Please please someone answer me I'll love you forever!

Thanks!

 

[bjc112]

Originally posted by: Shimmishim
there are better 2 x 1 gig sets... i can't remember what but i know there are some that can get up to 240 to 250

There is Rev. 2 Platiunum, but not worth the switch now over a couple of mhz..

Settle in on option 2..

Its really an effective DDR 390 which is no big deal.. You are holding relatviely tight timings as well..

2.7ghz is sweet on a X2.

You are good to go.

 

[thecoolnessrune]

Option 2 for sure. If you want a 1:1 divider, then sell your old memory and get some OCZ Gold Edition 2GB Kit. You'll run 4 Mhz slower but that will let you run 1:1. Even if you didn't get more memory, Option 2 is the best way to go.

 

[imported_michaelpatrick33]

I have my X2 4400+ at 250X11 with my memory running at 195 (Patriot 1gig dimms [2 of them]) with timings at 1.5-3-2-7 but I am thinking about getting the OCZ DDR250 1gig dimms that have 3-3-2 timings. Like you I am pretty happy with my performance but the memory makes me wonder.

 

[bjc112]

Originally posted by: thecoolnessrune
Option 2 for sure. If you want a 1:1 divider, then sell your old memory and get some OCZ Gold Edition 2GB Kit. You'll run 4 Mhz slower but that will let you run 1:1. Even if you didn't get more memory, Option 2 is the best way to go.

Gold would be the worst selection in this case.

EL Rev. 2 Platinum, which comes in nearly $75 cheaper as well..

Runs 2-2-2-5 @ 1T; Uses TCC5 - TCCD memory chips which typically allow speeds of 260mhz +

 

[lopri]

Bump for expert responses (Not that the answers above weren't helpful. Thanks a bunch, folks)

 

[lopri]

Update:

Currently Priming for 40 minutes @2750MHz.. I'm excited but it requires VCore 1.475. Idel temp went up from 33C to 36C. I've never up'ed the VCore this much before - would it be safe?

One more thing that I've just found: Up until I raised the VCore to 1.425, CPU-Z's reading was always 1.392. That is, whether I set the VCore at 1.35 or 1.425, it was always 1.392. When I set the VCore to 1.45, CPU-Z's reading jumped from 1.392 to 1.462. What is in fault? CPU-Z or my motherboard??!?#$

Bleh.. this is getting strange.

lop

 

[bjc112]

Originally posted by: lopri
Update:

Currently Priming for 40 minutes @2750MHz.. I'm excited but it requires VCore 1.475. Idel temp went up from 33C to 36C. I've never up'ed the VCore this much before - would it be safe?

One more thing that I've just found: Up until I raised the VCore to 1.425, CPU-Z's reading was always 1.392. That is, whether I set the VCore at 1.35 or 1.425, it was always 1.392. When I set the VCore to 1.45, CPU-Z's reading jumped from 1.392 to 1.462. What is in fault? CPU-Z or my motherboard??!?#$

Bleh.. this is getting strange.

lop

Could be the board overvolting slighty, no big deal..

Anything under 1.6v ( loaded ) is safe..

Personally, I wouldn't go above 1.55v, you typically get diminishing results..

It will probably take 1.5v to get that prime stable @ 2.75 or even 2.8ghz

Watch your temps, and keep them under 55c < ( 60 is ok )

 

[Thorny]

Originally posted by: bjc112

Originally posted by: thecoolnessrune
Option 2 for sure. If you want a 1:1 divider, then sell your old memory and get some OCZ Gold Edition 2GB Kit. You'll run 4 Mhz slower but that will let you run 1:1. Even if you didn't get more memory, Option 2 is the best way to go.

Gold would be the worst selection in this case.

EL Rev. 2 Platinum, which comes in nearly $75 cheaper as well..

Runs 2-2-2-5 @ 1T; Uses TCC5 - TCCD memory chips which typically allow speeds of 260mhz +

Platinum R.2 doesn't come in 1Gb sticks either, nor does any other TCCD ram so I'm told. I'd rather have 2Gb running slow than 1Gb running fast.

 

[Bull Dog]

Originally posted by: thecoolnessrune
Option 2 for sure. If you want a 1:1 divider, then sell your old memory and get some OCZ Gold Edition 2GB Kit. You'll run 4 Mhz slower but that will let you run 1:1. Even if you didn't get more memory, Option 2 is the best way to go.

I'm sorry but this *REALLY* bugs me. Let me make this real clear.

There is no such thing as running your memory at 1:1 timings with A64's
You memory is ALWAYS running A-sync.

Ram speed is baised off of a divider of the CPU speed.

My understanding outlined below.
A 3500+ runs at 2200Mhz.
The base HTT (hyper transport) speed is 200mhz and the bus runs a 5x multi on top of that, so one gets 1000mhz for the final HTT speed.

The CPU speed is also based on the base HTT speed. The 3500+ runs at 200x11 or 2200mhz.

The Ram speed is based on the speed of the CPU not the speed of the HTT bus. In the case of the 3500+, that translates to 2200/11 = 200mhz.

Now lets say you lowered the multiplier of the CPU to 10.5x The CPU would now be running at 2100mhz. Since the on-die memory controller doesn't support half multipliers you'll keep using the 11x divider 2100/11 = 190.9 mhz

Do you see how the only relationship seeming to be 1:1 is the fact that @ stock speeds the CPU and Memory use the same multi/divider?

1800/09 = 200mhz
2000/10 = 200mhz
2200/11 = 200mhz
2400/12 = 200mhz
2600/13 = 200mhz
2800/14 = 200mhz

 

[Bona Fide]

Go with 3, unless you're afraid of a non-integer multi. In that case, go with 2.

 

[lopri]

Originally posted by: Bona Fide
Go with 3, unless you're afraid of a non-integer multi. In that case, go with 2.

This is the core of my question. Is there anything that I need to be afraid of, with regard to a half-multi? I'm not afraid of it - actually quite the opposite. Because that, in theory, seems to give me the most out of my CPU and RAM. I'd like to know if there are any "inherent" disadvantage when using a half-multi.

I've been priming 2750MHz for 10 hours now, so now my options are as follow:

1. 10.5 x 261 = 2741, DDR333 = 211MHz
2. 11 x 250 = 2750, DDR333 = 194MHz

I did a quick Sandra test, and the CPU results are almost the same from both settings, but there are quite a bit difference between memory bandwidth. (option 1 scoring nearly 500MB better)

Another thing is that I haven't really seen anyone running non-integer multi's. "Why?" is my question.

Thanks alot folks.

lop