How does mouse dpi work in relation to display resolution.  For instance I seem to find my mouse jerky and not very accurate in games.  I play with my max screen res at 1360x768 but my mouse is only 800 dpi so could this be the problem.  Specifically in CoD4 my fps shows up on screen as being 91 max dropping to 70 but I dont seem to be able to target well with my mouse.  I do have to say however I still dont believe the 91fps the game says I have because it seems far too laggy and jerky for that.  BUT then could be the mouse dpi be my main problem?
 
Intel Quad6600
3GB memory
8600GT 256mb
Vista Home premium

double post...delete please

In FPS a lower resolution will give you more accuracy, but a higher resolution will let you turn around quicker.

ok,

dpi = dots per inch

think of it this way, a dot is equal to a pixel, the more dpi you have the faster the mouse can traverse the screen, so on a 800x600 resolution(with 800dpi mouse) you could traverse the screen(left to right) by moving the mouse exactly 1 inch.

first off what kind of mouse do you have? is it laser? ball? wireless?

a ball mouse tends to get clogged up and "sticks" causing this issue, a wireless mouse may be affected by nearby metal items also causing this issue.... a laser corded mouse has none of these problems the mouse wouldnt freeze, it would simply take a long time for you to turn.

if it is a laser mouse or led mouse, then it could be the surface you are trying to play on, i find a cloth mat or the wood of my desk are best for led/laser mouse.

this problem sounds more like an overheating issue to me.

The mouse Im using is a corded optical (led?) mouse.  I have tried different surfaces but the wooden desk Im using seems to give me the best.    I thought more dpi would be more accurate actually because there would be more increments to move across the screen, 1400 pixels being more than 800.  Im a bit confused thinking dpi would have some correlation to screen resolution.
 
Also does it not strike you as being strange that I get between 70 and 91dps on a cheap 8600GT when playing Call of Duty 4 online with 20 players?  You mentioned overheating.  Its the stock cooler thats on my machine I believe (machine was prebuilt) and its only an 8600 GT video card.  As for the case its got a 12cm fan on the front and a whopping 30cm fan on the side. Here is image of speedfan window and note I have CoD4 running  in background when i captured this image.

all of those temps, look very low.... i dont trust speedfan tbh, ive never had it tell me the truth, tend to use the software that came with my board(asus probe).
 
technically a higher dpi mouse would give you better accuracy, the way i mention about thinking of dpi is the easiest explanation.  
 
the other way is that a higher dpi captures more images per second, this is how a mouse tells where it is going, takes an "image" then compares it to the last to work out where it is, more dpi more images per second....(the images refer to the desk surface in microscopic detail that isd picked up from the led or laser of the mouse)
 
dpi does have a correlation to screen res, more dpi is better with higher screen resolution.
 
i only mentioned overheating because you say the game is jerky, why dont you lend a mouse of a friend, preferably a G5/G9/razer diamond etc and try it.
 
 
 

Im guessing you have adjusted the ingame mouse sensitivity?  If not, This can do wonders for mouse accuracy in FPS style games.

Refernce temps.  There is a newer (beta) ver of speed fan.
a good test is to (1) run newest ver of orthos and monitor temps, or load ati tools and run 3dview and mon cpu/gpu temps.
  There is also coretemp and MB utilities
 
as fare as 28/32 C idle temps, that depends alot on your ambient temps and case air flow and CPU fan.

I did adjust the sensitivity but to be honest I can never get it to be fast enough to suit me and be accurate. I think its too basic a mouse, and Im looking at getting a gaming one.
 
Its a Gigabyte mobo and there isnt temp monitor software with it.  Ill try Orthos and Core Temp

If your having problems shooting peps, meaning you seem to miis when your sure you have them in your sights..........You also say when playing COD4 online.  It could be the server or your connection.  Is it as bad when in solo play?  If it's only in multiplayer, then it's your conn to the net.  Whats your connection speed, use speedtest.net and speakeasy.net to find your ping in general and use the COD4 stuff to check your ping to the game server.

Joneb,  check your MB disk for easytune5.  I also have gigabyte board, the p965-DQ6

Some games actually lag with bad pings..

Make sure your mouse is not plugged into a usb hub, this can decrease the number in inputs/sec and make it less smooth....

800(higher just makes the mouse move even smother and see even your slightest hand shakes. so you have to be real smooth to use lets say 2500+) should be almost dead on perfect for that screen rez. I only use 800 most of the time...but if its too jumpy maybe you might want to try 600 or 400....

This is all a combination of your mouse and the in game settings too. Maybe try with Vsync on, on some games this smooths out the mouse

Some mice can run do more reports per second making things smoother(i noticed a big improvement), but the pain in that is needing an app to change the usb driver. Now all usb devices are unsigned.

What mouse are you running?

For temps, try core temp or speedfan beta. the old one reads 15c too low...your temps still look safe

Speedfan 1.34 beta no longer reads too low...you can adjust speedfan 1.33 with info found below

Adjust speedfan
http://www.tomshardware.com/forum/ [...] p-speedfan

Core temp download?
http://www.alcpu.com/CoreTemp/

I hope this helps some...

---------------
http://tinyurl.com/26uxxb - Core2 Temp Guide
http://tinyurl.com/cj3pw - VGA power use

First guys thanks for your replies.  Core temp reports my temp at 44 with basic use such as surfing but it goes up to 52 when CoD4 is running.  Is this bad or ok? For some reason Gigabytes Easytune 5 shows nearly 10 degress less again.
 
The problem doesnt seem very prevalent in the offline game.  In regards to pings I usually pick below 40 when choosing a sewrver in CoD4.  I tried Elwells Broadband Speed test which shows good pings but horrible packet loss.  However I tried pinging the bbc.co.uk server and it showed no packet loss on ten replies twice. If there is a way to check ping times and packet loss in the game can anyone tell me?  Ihave already been down the route complaining to Virgin.  Elwells speed test packet loss results is all I have to go on as manually pinging and checking for packet loss finds no problem plus the other speed tests only show broadband speed and all read fine. Virgin cant seem to do much if they dont see a problem.

Your temps are fine, There is a guide in my sig that will explain why the gigabyte software shows a different temperature(Tcase most likely)
 
For your pings and packet loss. This is in many cases out of your ISP's control since the world is linked and all it takes in one busted router out in the middle(on a different ISP) to drop packets or increase your pings.
 
In most games you can see your ping by hitting ~. For packet loss, i know of no way to test in game. If you use teamspeak it will keep track of such things. On average packet loss for most people is in the range of 0.3 - 1 percent. but this depends of servers and even the protocol used(way too much to type).

---------------
http://tinyurl.com/26uxxb - Core2 Temp Guide
http://tinyurl.com/cj3pw - VGA power use

 
Yes, this made a big difference for me.  My Logitech G5 makes up to 1000 position reports/second, while the MX518 makes only 125 reports/second.  Every now and then the G5 is on sale for around $40 -- go for it!
 

My 518(i did not try both, the second one is a logi replacement for my MX700 because i said...no more wireless) will do 500. and thats just fine by me for a 19 dollar mouse(Staples, damn i wish i got more)

You should try the 518 again...i think they would all do it....but hey they changed it once...first ones maxed at 1600dpi and now its 1800 for some reason...

---------------
http://tinyurl.com/26uxxb - Core2 Temp Guide
http://tinyurl.com/cj3pw - VGA power use

I was playing CoD4 last night and when there were only 5 of us in the game everything was much smoother for me but when there were 20 there was visible lag, avatars moving large increments and major jerkyness when alot of action was happening.  The default quality stting that the game picks up is 800x600 resolution but i turned it up to 1360x768 and the fps doesnt seem to go below 40 still.  800x600 is not comfortable to look at on my 32" 1360x768 screen and Im sure it didnt makemuch performance difference but I wil check that again.
 
Could it be that my video card is too poor for this game at the setting of 1360x768  even although the fps is between 40 and 90 (mind everything else is turned down lowor off)?  Urgh there are so many variables.  Do any of you think I would benefit from a 8800GT video card update and a gamer mouse?

Well since you say its less smooth with more players you are almost certainly seeing others pings effecting things.

Even if you have a nice low ping of 40. The other guy with a ping of 200-400 may appear to be mini warping....

Check out the pings of others.

There may still be a graphics limmit. The more players the server has the more your computer has to render(more players, bullets, explosions, and other items they interact with.) Even when you can not see it the computer is rendering it. Thats the unfortunate reason why wall hacking works.

I would recommend trying different servers(since its not just server pings but user pings that effect game play) and seeing if you can turn down some of the in game settings. turning off shadows, AA and down shader levels can improve performance at the cost of visual quality.

A gaming mouse will do nothing to help if the actual game play is jerky.

---------------
http://tinyurl.com/26uxxb - Core2 Temp Guide
http://tinyurl.com/cj3pw - VGA power use