are you running piplay in X or from command line? Also, in raspi-config, did you expand your filesystem and split your ram (I recommend at least 64 mb to gpu, I personally use 128 mb). Last thing, are your roms stored on a fast enough card? one thing that can greatly speed up the read write of your card is to use the SDformatter program by trendy, set the format option to 'full (erase)' I did that a little while ago when I was staring down a 6 hour file transfer. After the full (erase) format, it became a 30 minute transfer (plus another 20 minutes or so for the format).

Here's a script I use through putty to monitor the speed converted to MHz and the temperature of both the CPU and GPU converted to Celcius while playing a game. I setup an alias so it was easy to do quick up arrows several times to monitor it. I am sure someone with better skills could modify it to run at a timed intervals or other features.

I think the "ondemand" governor kicks it down at 85C so if you're hitting that cap for some reason it could be the culprit to check like being enclosed in a heated environment.

What emulator and games are you running?

#!/bin/bash
cpuSpeed0=$(cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq)
cpuSpeed1=$(($cpuSpeed0/1000))

cpuTemp0=$(cat /sys/class/thermal/thermal_zone0/temp)
cpuTemp1=$(($cpuTemp0/1000))
cpuTemp2=$(($cpuTemp0/100))
cpuTempM=$(($cpuTemp2 % $cpuTemp1))

gpuTemp0=$(/opt/vc/bin/vcgencmd measure_temp)
gpuTemp0=${gpuTemp0//\'/°}
gpuTemp0=${gpuTemp0//temp=/}

echo
echo CPU Speed: $cpuSpeed1" MHz"
echo
echo CPU Temp: $cpuTemp1"."$cpuTempM"°C"
echo GPU Temp: $gpuTemp0

@mholgatem - Could you explain how to expand the filesystem and split the ram like you mentioned?

@sadeter

sudo raspi-config

option 1: Expand Filesystem

option 8: Advanced options
∟option A3: Memory Split

I am so fed up at the moment that I might just format everything and start over.

This might be the problem. I am going to use a separate sd card for xbmc and for piplay and hopefully that will sort the problem.