Folks, this is my review of the Dell 990 with 8 gigs of ram and a 2tb hdd.  The machine I received was sold by Skytech.  The first thing I did was look under the hood, sorry folks Ima auto mechanic thats "open the case" for normal folks. My machine was manufactured 11/2011.  It has been completely disassembled, I can tell by new paint on the exterior and slight overspray on an interior piece. It also appears that the case itself was disassembled because it has new rivets holding the exterior case to the interior frame. Also 1 rivet was loose and bouncing around inside the case. If you hear anything loose when u receive your computer, open the side and dump it out. Folks, these machines are tossed around like volley balls by the delivery guys. Common sense would be to visually inspect the inside for loose or damaged components  before you ever plug it in. These are refurbished machines. They are NOT NEW. When these machines were new, they were the top of the line for Dell. They are extreme workhorses even at todays standards. The 2tb hdd does make noise but I found on mine that it is not so much the hdd but the rack the hdd is mounted in. It rattles. I found a small piece of rubber hose between the hdd and the rack completely solved that problem. As for the operating system, Win 10 pro 64 bit activated with no problem. And of course it is a 64 bit processor.  These machines are rated for 16gb max ram. I ordered mine with only 8gb to save a few bucks. It came with four 2gb sticks installed. For my needs 8gb is sufficient. I did do some research on this machine and it has been run with 32 gigs of ram installed and said to be working perfectly. Check it out yourself. Google is ur friend...use it. I would suggest only 1 thing and this actually covers any machine with a hdd. Buy a ssd to use for your main drive.  Using Crystal Disk Mark, this machine read/write the hdd at 112/110 MBs . I put a used ssd I had in it and brought the read/write speed up to 560/480 MBs! Thats exactly 5 times faster read speed! This machine is a beast! I just cloned the 2tb to the ssd and use the ssd for my main drive then reformatted the 2tb and use it for storage. I also added a GeForce 210 video card and a PCIe USB 3.0 card. The internal video card has VGA and Display Port outputs but I wanted to run two 32" tv's as monitors without buying adapters. With the added video card (new the cards are around $40) this machine runs the two 32" tv's as dual monitors beautifully. I would also recommend the additional usb 3.0 PCIe card. It has I think 10 usb 2.0 but 3.0 is so much faster, Its well worth another $30-$40 to add this on. This machine has 1 PCIe x16 slot, 1 PCIe x4 slot, 1 PCIe x1 slot and 1 PCI slot. Folks, I am very pleased with this machine and highly recommend it. I can also recommend Skytech as a seller because being a mechanic, I can tell good workmanship vs something just thrown together. The guys at Skytech did a nice job with this machine. For this price if you add a few upgrades you will have a machine that will once again be top of the line. But folks, dont expect a brand new top of the line machine for $200 straight outta the box. This aint 1980!