To start off with, I'll provide my system information:

 

Windows XP Home SP2

Intel Celeron T1400 (1.73 GHz)

1GB RAM DDR2

Mobile Intel 965 Express Chipset Family

 

Also take note I'm not keen on it, so I might miss important information while giving above data.

 

While playing Runescape my FPS circles around 5-15 (all FPS values were measured in large dungeon), even though i have TuneUp Utilities installed, all unnecessary processes closed, Java priority set to highest, using Runescape official client and playing in Fixed Safe Mode. Sometimes, mainly after logging in my FPS suddenly jumps to 30-35 and stays so for a couple minutes, then is again lagging @ 5 FPS.

 

Is there a way to improve average FPS by other way than buying new hardware? If no, then tell me what parts are needed to be changed to improve performance. Constant lagging is very annoying to me, because i DG a lot and my doorlags time averages around 4-5 seconds, keen dungeoneers will know this is an enormous amount.

 

I appreciate all answers, thanks in advance.

I think it could be an overheating issue. Where do you use your laptop?

 

Run this utility while playing. When it starts to lag see if there are any temperature changes.

Just so you know it is very hard if not impossible to upgrade laptops.

 

It seems like some other process is using all of the processing power and stealing it from RS. Try monitoring your CPU usage levels and seeing which processes use significant amounts apart from RS.

 

I wouldn't expect massively high results from that computer though - those specs aren't great.