Right after I started using my USB flash drive for Windows readyboost I started getting stutters in games at random intervals, usually 30 seconds to 2 minutes between stutters. I had these playing both COD4 and TF2 (didn't test with other games). I did some investigating with Hardware Monitoring in Rivatuner and in COD4 it seemed to coincide with my GPU core/mem clock speeds temporarily dropping down to the 2d mode speeds randomly in game. So naturally I used Rivatuner to set hard clock speeds and although my clock speeds stayed constant I still got stutters. As soon as I unplugged my USB flash drive it was fine. Also, I was using one of the fastest and highest rated USB flash drives, a Patriot Xporter XT. I am assuming this was caused by Readyboost caching necessary game files to the USB drive that it shouldn't be.  
 
I was wondering:  
Has anyone else had this problem with Readyboost?  
Do you guys have any idea if this is unique to my system, unique to ATI cards, or maybe just unique to the 3870 series?
Is there a fix?
 
I know I don't really need readyboost since I have 2 gigs of ram, but still I found this interesting. My system Specs are as follows:
Motherboard: Asus Maximus Formula SE
MEMORY: 2GB Corsair XMS PC6400 C4 @ stock speeds
CPU: Intel Core 3 Duo e6850 @ stock speeds
GPU: Diamond Viper ATI Radeon 3870 @ 825/1276 OC
Windows Vista Home Premium 32 bit.

I would look at getting a faster usb thumb drive for use as a ready boost drive, that said you most likely don't need it.

Other then the speed of the drive, or a possible driver issue one other thing you could check is to make sure your motherboard USB ports are set to highspeed and not fullspeed. My ASUS board came defaulted to fullspeed which is only 12MB instead of 400 (Could not for the life of me figure out why it was taking hours to upload tunes to my mp3 player).

After installing Vista one of the first tasks I did was disable readyboost. It's a useless feature that really doesn't help as much as it was praised to. I personally would not bother with it and disable it yourself, especially since it started to lag your game.

I'm wondering if Readyboost will get a boost from USB 3.0 or whether it will be unnecessary with the new flash drive chips which may be out:
 
http://www.tomshardware.com/2008/0 [...] sh_memory/