I thought that there was the 1.93 ROM update??? I might be mistaken.
What Tweaks do you have?
My wife has nothing running in the background and still the phone is real sluggish. I remember my VIII and really liked it. It done almost everything. The Compact IV doesn't even come close - not even at making a simple phone call!
I'll browse this site a touch and see if I can add any Tweaks.
@ Paul - have you done a "Tweak" for the Diamond like you done for the VIII / Tytn II?
You have a very old ROM, and no amount nof tweaking is going to make much difference
1.37 is inherently slow, and presumably the Radio is still 1.00.03?
T-Mobile are sending repaired units back with ROM 1.93, but some new devices are still being supplied with 1.37, which is a joke. Also, T-Mobile UK have not released a ROM update. Indeed they don't even list the Compact IV in their support site.
So, to get a major speed increase and better phone/GPS/WiFi performance, your only option is to install an 'unofficial' ROM, or even an 'official' HTC ROM. Both of these require the installation of HardSPL before proceeding, otherwise the update WILL fail. This is a painless process, and if you want to proceed, someone will guide you
Once you have HardSPL, you can then flash any available ROM version. Be aware that a ROM upate (and installing HardSPL) does clear all the contents from your main memory. It also risks invalidating your warranty, but there is no eveidence that any operator has actually invoked that excuse.