ideal X2 cpu advice?

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over the next week i'll be buying a new dual-core X2 system for 3D

i'm trying to keep the cost down, as a good portion of my budget will be
going on a shiny new 7800GTX :) however i would like to OC whatever chip
i get up to around 2.6GHz... i already have 2x1GB of budget ram which i
would like to use in the new system if it will oc enough... ?

my options are either buying a cheaper X2 3800+ or 939 opteron, and with
some new expensive ram i could oc to 2.6.  but would it also be an
option to buy a 4600+ which runs at 2.4 stock, and use my current memory
[kingston DDR400 3-3-3-8] to reach a 2.6 oc...? the latter option would
be WAY cheaper for me... but would it actually work or am i a spastic
newb?  btw the mobo will be a DFI SLI-DR Exp.

Re: ideal X2 cpu advice?

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I have a 3800 X2 Manchester core, prime 95 dual core stable @2750 1.475vdc
however I'm told that is not a typical overclock for a 3800 X2, more likely
would be 2400-2600.  I bought mine for 279$ at the fry's black friday
special.  Opterons S939 supposedly overclock better.  However I've never
owned one so I will let someone else speak on this subject.

Overclock as a % for a 2000MHZ 3800 X2


anything over 120% is a lot of free cycles especially since 4600/4800 X2 run
at 2400 and run 630$/787$ at newegg

As for your ram A64 S939 boards are designed to run memory asynchronously.
For instance while my HTT (or FSB) speed is 10X275 my ram is running at 5/6
speed (DDR333) or 229.  I have my memory set to 1T and get the SANDRA
results below. I do have to admit I'm running PC4000 memory.  Lower memory
dividers are available so buying memory is something you don't have to do
right away and your have an advantage with the DFI board as memory can be
extremely tweakable as well as having a higher Vcore setting

RAM Bandwidth Int Buff'd iSSE2 : 6607 MB/s

RAM Bandwidth Float Buff'd iSSE2 : 6482 MB/s

basically there are three steps in overclocking an athlon 64/opteron

DFI overclocking information

A beefy PSU will go a long ways in keeping your system stable.  My 3800 X2
runs 89W stock and 133W overclocked with both cores at 100%.  That is plus
44W or close to 10% more power my 535W enermax has to produce to keep my
overclock stable.

Good luck.  The net is your friend in gathering information to make an
intelligent purchase choice as well as how to get the best overclock/

Re: ideal X2 cpu advice?

Leadfoot wrote:
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but that would still be cheaper than me having to buy some highend ram
which here in NZ costs about NZ$600, plus another $600 for the opteron
or 3800+, $1,200 total.  as opposed to just $900 for a 4600+ and using
the ram i have.  or are u sugesting that my ram still has potential to
get a 2.6 oc with a 3800+ without crippling the bandwidth/timings..?

anyway thanks heaps for the links i will read 'em thoroughly to get a
better understanding. (i have an 80% efficiency PSU, Seasonic S12 500W.)

Re: ideal X2 cpu advice?

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Keep reading and keep surfing from those links, there is no need to run your
cpu speed and your  memory speed at the same frequency.  UNLESS you really
feel the need to run them at the same speed.  One of the neat things about
the A64 is that the memory controller is on the CPU NOT on the motherboard.

Remember the the three steps to overclocking an A64 system?  You really need
to read step two where you overclock the memory

"Go into the memory section of the bios and set the memory speed to 200mhz
(1:1) this means that for every MHz you increase the FSB you increase the
speed of the memory. Again leave the CPU at 6x so it does not become the

Now in my case to achieve 1T the memory has problems around 235MHZ to get
there. I use a 5/6 divider or 333/400 or 83% of 275 or 230MHZ.  I test this
by setting the cpu speed to 6x275 or 1650.  That way the overall CPU speed
is not part of the equation to find memory speed.

In short I would test what your present memory will do with whatever
CPU/motherboard combination before I bought something else

I would definitely buy the 3800 X2 over the 4600 X2 and take my chances
overclocking it becasue 2.4GHZ isn't a hard overclock providing it's a 90nm

What are the markings on your kingston memory chips?

Your seasonic should do fine

Re: ideal X2 cpu advice?

Leadfoot wrote:
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ahh ok. i will do an OC test with my kingston ram on my current rig
which is a 3200+ (754).  overall my current VIA rig is not a good OC
solution, my Albatron K8X800 ProII doesn't have PCI lock.  one of the
things i've read is that OCing without PCI lock is the quickest way to
get hard drive coruption once you go up a couple hundred MHz, something
i can't take a chance on.

Re: ideal X2 cpu advice?

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 So try this, /
 Run it from a bootable floppy or cdrom. You can even disconnect your
HD if you're worried. You can slowly crank up your settings until you
start getting errors. That way you'll have some idea as to what your
memory can do. I've got some Kingston Valueram 1 x 512MB to run 234 MHz
on a  Asus K8V SE Deluxe, timings 2.5-3-3-8, for 24 hrs with no errors.
 Voltage set to 2.7Vdc. The hard drive is not even recognized by the MB
at that speed, but since I'm not running off the hard drive, no


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