Hi there !

I have asus p5b deluxe 4GB RAM and Dual Core E6400 @ 2,6Ghz. I have bought GTX560 1GB and skyrim is runing nice, but I need to have shadows low/medium. With higher settings it becomes laggy and mouse is delayed.
The question is, if CPU upgrade would help - I think of some cheap upgrade for CPU my old LLGA775 mainboard,
I was thinking about
1) Dual Core E7600 and overclocking to maybe around 333x11.5 = 3,800 Ghz - this is worth around 100Euro
2) Quad Core - cant get new one from shop, maybe I can find some Q6600 or Q8300 and overclock to around 3-3.5 GHz

so question is - if it is going to help for shadows and if E7600 is worth the upgrade

thanks for help !

You could be running into a CPU bottleneck. If I was you I'd hold out for a Q8 series then that would be better, since the Q6 series runs hotter and they came with much bigger heatsinks.

I done a little testing on my laptop a few days ago (more to do with 2 core turbo mode testing) and dual core overall performance was lower and loading times higher when I limited SKYRIM to use just 2 fast cores over 4 slower cores. But overall perceived smoothness is helped by just having a faster core speed even if its only a dual

shadows really are a CPU limited hell with skyrim

if you go for a q6600 off ebay and clock it to 3.5Ghz you can enjoy a smooth 60fps potential at medium shadows, if you want high shadows look towards a overclocked CPU at around 4.2Ghz

thing is skyrim wont max your CPU out, the limitation with shadows is inside the games engine (even though it does scale with CPU speed) so even if you had 5Ghz a core CPU your shadows potential would be limited with the game using only 60% per core.

The Engine front end speed at 64Hz may have some factor in shadows limitation, it definitely has physics sync issues with 60FPS displays cause of it (64Hz/59fps frame limiting is no myth), If the shadows were multithreaded, the game would run at high shadows on a default clocked q6600 or ultra on a default i5-2500k.

It's got more to do with the architecture of the CPU than the Mhz. 4096 ultra shadows require more GPU power, not processing power and there is zero need to use ultra shadows because the engine doesn't allow proper ultra quality anyway.

CPU architecture i cant speak for but CPU scaling based on speeding up the CPU's architecture (or grading) has a noticeable effect

I'm not saying ultra shadows doesnt require more GPU power, i know it does because my old 6950 crossfire used to hit 100% usage on each GPU with shadows on ultra.

But CPU speed does have a major influence on shadows distance/quality, and tuning shadow quality to you CPU speed is the primary limitation of how smooth the game can run. Turn off all other settings or lower them to the lowest setting other than "shadows and object distance (add NPC shadows ect if you want)" and measure the game with fraps in high shadow area (The waterfalls ledge at Calcimo's tower for instance). I doubt you'll see 60FPS measured by fraps with less than a quad core running at 2.6Ghz for low shadows, 3.5Ghz for medium, 4.2Ghz for high or 5Ghz or more for ultra.

Ive tried scaling my 2600k. at default speed medium shadows didnt limit the game engine and ran it perfectly smooth, 4.2Ghz high shadows were perfectly smooth and 4.9ghz ultra is 95% smooth at all times. Certain area's at ultra i loose that 5% and im dragged down to 55 frames at those points.

its independent from the graphics quality/resolution and the difference is perfectly smooth motion or jittery motion when you move the mouse

Ultra shadows is achievable with how they have programed the shadows code, and shadow resolution doesnt seem to have much effect, but it's ridiculous the CPU speeds needed for shadows on ultra, and needs to be fixed, as 5Ghz i5-2500k equivalent for a purchasable non overclocked part wont be seen for 2-3years

and shadows on low svcks ass on my 740QM-GT435 mobile, and that fairly modern hardware

That's why people shouldn't waste their time on ultra shadows because they're pointless. Seems to me that using raw power to go to where you wan with this game is terrible. You just have to face facts and that is the engine is poor, thanks to Bethesda's corner cutting and budget skimping on such a massive title franchise game.

ultra shadows (8000 distance) with 8192 adaptiveAA/CCAA filtered shadows looks beautiful, and if you got the gear or want them you should go for them

really makes a massive difference, especially at 2560*1440 ultra

they need optimising though

So I have searched, and found some CPU. I have Arctic Freezer 7 Pro cooler, so I will definitelly do some overclocking
I have this options - which should I go (if any...) ?
used Q6600 2.40 Ghz 108Euro (probably will go to ~3.00 GHz overclocked)
used Q8200 2.33 Ghz 105Euro
new E8400 3.00 Ghz 130Euro (probably will overclock 3.4 GHz)
new E7600 3.06 Ghz 108Euro

Make sure to check up on the FSB frequency on any CPU you are considering. The Asus P5B does have the capability for the BIOS to be flashed to accomodate a 1333 MHz FSB CPU like the E8600 but once you flash it past the 1066 MHz manufactured rating you can't go back. The BIOS flash is official and can be found on the ASUS site.

Q6600 ---> 1066 MHz
Q8200 ---> 1333 MHz (flash required)
E8400 ---> 1333 MHz (flash required)
E7600 ---> 1066 MHz

Personally I run the E8600 3.33 GHz CPU on a native 1333 MHz MoBo and it performs quite well. I run the shadows on high. I've never needed to OC it however this generation of CPU's were very overclockable as they were based on the 45 nm process and didn't produce excessive heat. A good aftermarket cpu heat sink is always recommended though.

The E8600 was the fastest Core-Duo they made and I'd recommend it if you can still find one.