Lightroom 4 becomes slow again with 4.2

Question

Photography is my hobby and not my job. So I don't want to spend a lot of money to treat my raw files: I prefer to spend my money in camera and and lenses.
I've got an old computer like this one and I don't want to change it immediately.
Version de Lightroom : 4.2 [850741]
Système d'exploitation : Windows Vista Home Edition Service Pack 2 (Build 6002)
Version : 6.0 [6002]
Architecture de l'application : x86
Architecture du système : x86
Nombre de processeurs physiques : 4
Vitesse du processeur : 2,4 Ghz
Mémoire intégrée : 3325,5 Mo
Mémoire réelle disponible pour Lightroom : 716,8 Mo
Mémoire réelle utilisée par Lightroom : 451,1 Mo (62,9%)
Mémoire virtuelle utilisée par Lightroom : 489,3 Mo
Taille de la mémoire cache : 0,0 Mo
Paramètre PPP du système : 96 PPP
Composition sur le Bureau activée: Non
Affichages : 1) 1280x1024
This computer is 4 years old but in accordance with lightroom's specification.
I used it with Lightroom 3. Sometimes it was slow but it wasn't a problem.
I tested lightroom 4.0. It was unusable with it.
With lightroom 4.1, there was no problem. So I decided to buy it.
With Lightroom 4.2, problems come again. I remove the old preferences files, optimize my computer (my computer is dedicated to lightroom, no other software runs during photo treatment).
It's always the same. Lightroom runs at a good speed and slow ten minutes after opening (and freeze sometimes).
Please Adobe do your job!!! You take our money and nothing progress. We can't wait like that. If we need to find a solution and optimize our computer by ourself, the best solution is to switch to an other software.
That's the first time that I write something in a forum like that. I decided to do that because I'm very angry to spend so much time to treat my raw files. I prefer to spend my time (and money) with my camera...

Answer 1

Just another opinion.......
I have been using Lightroom (all versions) for many years now. I am currently on lr 4.2 along with Photoshop CS6 standard.
I use a Windows Ultimate 64 bit dual xeon 2.6 processor using 12GB RAM And a 1GB ASUSGTX550 Ti graphics card. RAID disks and separate disk as a scratch disk.
I work primarily with Canon EOS 5d MKII raw files. 21MB each. I make colour corrections in LR then use photoshop for more creative enhancements.
For the most part my experience with Adobe software is a positive one. For me moving from LR 3 to 4 I noticed a performance drop in the software. However I rationalised this against the software could do more. I cam sympathise with some of the other posters as areas of decreased performance for me are:
Slower 1:1 Renders
Slower export of JPGs. (Although I've noticed the more enhancements I make in Develop mode, the slower the export time)
latency when making adjustments
As a submitter of stock libraries, the performance decrease is an incovenience but not a show stopper and doesnt impact my workflow to heavily.
Interestingly Ive noticed the performance of CS6 increased for me when I upgraded. Ive watched a lot of Adobe/Linda tutorials on setting up Photoshop and they all mention the Mercury graphics engine in CS6. Now I'm not sure on the technology of Lightroom, but would it perhaps benefit from the same technology?
The biggest bug bear for me is the latency on making adjustments. For example if I open a picture in Develop. Then adjust Exposure. The slider acknowledges the new value but the preview needs time to catch up.Again it's not the end of the world for me. But if ayone know of tweaks or enhancements I could make to LR to improve this area, that would be greatly appreciated.
I would like to close by saying. I believe LR is a great product and along with Photoshop they compliment each other very well. IF LR performance could take the same step as Photoshop I believe LR would become a fanstatic product not just a great one.
Thanks for reading.
Neil