Uninstalled FSX and cleaned up; Reinstalled FSX then applied SP1 to a clean install - result much better frame rates however ....Using (more or les) my previous FSX slider settings I have noticed much more HDD activity so much so that in certain ares of my 'test flight' there is so much that the sim stops completely for a minute or so then resumes.Is there an issue with SP1 and RAM/Disk caching which can cause this?If yes, is there a cure?!!MTIA for any help as this is the only thing now which is affecting the performance :)

I don't know about issues but some suggestions might be:1. More memory = larger disk cache2. faster drive - e.g. a SATA drive if yours isn't3. defragmenting 4. Having fsx in its own partition - if it is in a very large partition then some files may be at the start of the partition and others at the end, more disk head travel time- makes defragmenting faster too

Thanks for the suggestions - I will certainly give them a try where I can (btw, updated my signature - my HDD is SATA).Cheers, again,

>Uninstalled FSX and cleaned up; Reinstalled FSX then applied>SP1 to a clean install - result much better frame rates>however ....>>Using (more or les) my previous FSX slider settings I have>noticed much more HDD activity so much so that in certain ares>of my 'test flight' there is so much that the sim stops>completely for a minute or so then resumes.>>Is there an issue with SP1 and RAM/Disk caching which can>cause this?>>If yes, is there a cure?!!>>MTIA for any help as this is the only thing now which is>affecting the performance :)FSX most certainly uses more memory than did FS9, I've seen greater than 1GB on my 2GB system, so it will definitely swap out to virtual memory on a 1GB system like yours. The only way to prevent this, is to either reduce your scenery, so the sim uses less, or adding another 1GB memory to your system.

If you can, separate the FSX, System and Swapfile partitions onto different disk spindles.Many users forget that in a physical hard disk drive the head(s) can only do one read or write at a time. If you have FSX trying to get a texture and the operating system trying to page something in or out and both i/o requests are made in FSB time then head contention can occur which can slow down your i/o considerably and cause performance issues in FSX.John