need some directions.

[ilikeoatmeal]

Hey, I've not posted in over 6 months because I ran out of money to finish building my system. Well, now i've got a job and can afford the video cards I never bought before.

What is better? 1 7900GTX, or 2 7900GTs? And which brands are best nowadays? As soon as I buy the cards I'll be doing the first startup.


Next... I've got an A8N32 SLI deluxe motherboard, 2gb Corsair 3500LL Pro DDR, 1 GB generic DDR, and an Opteron 170 (OSA170CDBOX Stepping E6 CCBWE) cooled with the stock AMD fan and heatsink, along with 5 other case fans. My PSU is an SLI compliant 550W Sunbeam Nuuo. My OS will be Microsoft Windows XP Professional x64 Edition. Tell me what I need to do, as specifically as possible, to overclock this bitch without ruining my system. And if you need any more info about my system, then by all means ask.

Thank you.

[amjedm]

I honestly thought you were after some directions to a place. Why not change title to 'need some graphics card advice'?

[leeglf]

take a left at the third island and right at the traffic lights

[Syd]

I would personally go for the 7900GTX, as that will give you best performance in ALL games, at most resolutions, then 6 - 9 moths down the line, add a second card IF you need it.

If you want comparisons check out toms hardware guide

[amjedm]

I would personally go for the 7900GTX, as that will give you best performance in ALL games, at most resolutions, then 6 - 9 moths down the line, add a second card IF you need it.

If you want comparisons check out toms hardware guide

Can Tom's be trusted for the information? I don't visit them myself - just what I've heard from other people.

[kalniel]

You just follow the signs to the 2d/3d forum subsection

[MantisCSS]

lets acctuarly help the guy! i personaly would go downt he lines of the GTX m8, liek syd says u always then have the option do upgrade further down the line. at the moment the GTX will handle any game out there, i had 2 7800 GT's and allthough looking back i think yeh, they did look like the Dogs B*****ks arcticaly silenced i prefer having the GTX, due to i now have the option to buy another and my system temps r lower. im not to sure about makes. all i could suggest are XFX, leadtek, BFG.

Good luck!

[ilikeoatmeal]

yeah but everyone read the second part, about telling me exactly what i need to do to overclcok my system right.!!!!

[Syd]

yeah but everyone read the second part, about telling me exactly what i need to do to overclcok my system right.!!!!

Sorry not my area of experience, but you were asking two questions, right!!!!!!

[-ChEM-]

overclocking basically entails increasing the HTT, this and the cpu multiplier give the cpu speed

htt x cpu multi = cpu speed
which is currently 200 x 10 = 2.0ghz

however, when you increase the HTT you also change 2 other things in the same way, the HT frequency and the memory speed

memory can be overclocked but its a whole nother issue with timings vs bandwidth, voltages etc so forget about it for now... all you need to know while you overclock the cpu is how to keep the memory and HT at safe values

htt x ldt = ht freq

this one is easy, the ht freq has no impact on system speed so it doesnt matter what its set to, as long as its not too high or too low, and the range it needs to be at is around 750-1100 (all A64 chips are 800 or 1000 at default) so if the htt is 200mhz-265mhz set the LDT to x4.0 and if its above about 265mhz put it down to x3.0

htt x divider = memory freq

the divider will currently be on 1:1 so that htt = memory freq (200mhz HTT = 200mhz = DDR400)

when you increase the htt to say 240mhz, the ram will be at 240mhz aswell which is too fast to be sure its stable, so you need to put it on a 166mhz/DDR333/5:6 divider which means the ram will run at 200mhz/DDR400 again

if its running faster than stock you need to increase timings and/or voltage which makes the whole business of OCing the chip and lot more complicated, stay away from it and keep the RAM at stock (or better still underclocked) while youre dealing with the chip

once youve found a limit for your chip you can then choose a good divider for the ram... it will probably be a choice between slightly overclocked ram with loose timings or slightly underclocked ram with tight timings, you can bench both with say 3dmark if you want 3d performance or sysmark if you want encoding performance and see which is best for you later but it wont matter much

note theres some rounding in how the ram speed is calculated on a divider so for example my HTT is 300mhz, the divider is 133mhz/DDR266/2:3 so you would expect a ram speed of 200mhz/DDR400 but its actually 192mhz

to actually start overclocking, first thing i would do would be to lower the dividier to 133mhz/DDR266/2:3, lower the cpu multi to x5.0 and lower the LDT to x3.0, then raise the HTT to 300mhz and run some prime95 testing (use this program http://sp2004.fre3.com/beta/beta2.htm on the small FTT setting for an hour or two)... you should have no problems doing that and it will ensure your board can do 300mhz HTT which is enough to max out the cpu you have

then you can begin with the CPU, raise the cpu multi to 7.0x (2.1ghz) and boot windows, run some prime tests if you want or keep going, keep raising the cpu multi until your system is unstable... it should do between 7.5x and 8.5x on stock volts

once its unstable, increase the core voltage / vcore and try again, start at 1.400v as the first setting, and go up to 1.550v but increase it gradually as too high a voltage could make it worse

keep going until you find the maximum multiplier you can use, it should be easy as you are dealing with steps of 150mhz which is a pretty big jump

then you can find a more precise limit by tweaking the HTT, say you have 300 x 9.0 stable but 300 x 9.5 unstable... lower the HTT and increase the multi so you are at the stable speed you found before, in this case 270 x 10.0, same as 300 x 9.0, then increase the HTT slowly and find your max stable speed

if it can do prime tests for 12 hours you're ok

[ilikeoatmeal]

that is extremely helpful. thank you very much.

[taqies]

excellent advice -Chem...