As I understand Dedicated Card may be NOT user (or even technician) upgradeable if it is soldered onto the system board and can not be physically removed by the user at a later time...so question is unclear for me.
I doubt that they are upgradeable. Very few systems allow for this. If you look at the description for the term "user upgradeable" on xotic's site, they state that even if you can replace the card, you may not be able to put a newer card into the system. Some motherboards just don't allow it.
For example, I had the ability to upgrade the 7950GTX in my system with an 8800M GTX since they worked off the same slot type. However, there were issues with such upgrades and it meant a motherboard replacement as well.
Bottom line: I wouldn't purchase a laptop with the idea of upgrading it down the road. That being said, the HD 4870X2 should be a very capable card.
,,even if you can replace the card, you may not be able to put a newer card into the system. Some motherboards just don't allow it.,,
It is a primary problem which I am afraid of first of all!
Really, if the manufacturer does not state some laptops as "user upgradeable", that may also mean laptops are upgrade protected.
Visually all may look the same like "user upgradeable", PCI-Express slots are ok but BIOS or even a special chip on to motherboard may check for videocard's match: are it proper or not.
And after videocard replacement you may find that your laptop does not start anymore (may be BIOS will show you an''unknown hardware error,, or something like this).
I remember the examples from similiar areas: few years ago Nokia, Sony Ericsson phones usually did not support ,,non-native,, USB cables because these phones did a check for small chip integrated in these ,,native,, USB cables.
Sometimes it was enought to get a refuse just trying to use the same Nokia cable but designed for different model of Nokia phone.
This way customers who need USB were have to buy about £20-25 Nokia cable even when old USB Nokia cable was available!
''Bottom line: I wouldn't purchase a laptop with the idea of upgrading it down the road. That being said, the HD 4870X2 should be a very capable card.''
Yes, even if a laptop is stated as "user upgradeable" you may find that new generation's cards are not compatible to your system athought they match to PCI Express interface completely.
For examle, power consumption/peak power consumption may be too high.
Yes, the HD 4870X2 should be a very capable card - this and next year i think, and this is the reason why I stick to Asus W90.
But another way it is better to have a possibility for further upgrade.
I just upgraded my old PC recently: GeForce 4 AGP 8x consuming up to 40-60 W fan cooler enabled to low-end GeForce 7 AGP 8x without any fan with top consumption less than 50W.
Yes, it is not modern enought, not good for Crysis etc. but better than nothing, better than just trow it out )
But the problem is that W90 is still very new and video cards installed are almost the newest and an alternative video cards attractive to try (like nVidia GTX 280) are the newest...
This way I think there are almost no hardware / performance enthusiasts who just made a succesful tests, how to replace HD4870 X2 to alternative or tests which shows this is impossible.