Upgrading the 2X2.66GHz quad-core Mac Pro(early 2009, 5,1) in 2024
I am living in South Korea(I am not an engineer. English is not my native language.) and I have a M1 MacBook Pro, a G4 and a Macintosh II. And I recently bought an Mac Pro A1289, early 2009, dual CPU, firmware 5,1(originally 4,1). It was an old system but I bought it because it was still good and also very cheap. It did not work; the seller did not know how fix it. Its firmware was flashed to 5,1 and six 2 Gb rams were already installed. For the first time I replaced the power supply and installed two DDR3 16Gb 1333MHz ECC Samsung RAMs on #1, 5 and four 2Gb rams on #2, 3, 6 and 7. #4 and 8 remained empty. The system did not work(display was white screen). So, I removed every 2Gb rams. Now it works. 16Gb rams are on #1 and #5.
I have many 1/2/3/6TB HDDs to install and about to upgrade the CPUs, add new SSD and rams, and also update Mac OS for this workstation soon.
1) Can I install both 16Gb and 8/4/2Gb rams on one system? If it is possible, how to arrange them? Or this won't be good choice?
2) If I buy 1600MHz 16Gb rams, they can be installed with 1333MHz rams?
3) The Mac Pro shows me that the memories are 1066MHz although I installed 1333MHz ones. 1333MHz or 1600MHz rams are all become 1066MHz on the 2009 system?
4) The graphics card is ATI Radeon HD 5770 1024Mb. If I set the resolution to 2560X1440, it's my monitors max res., the display becomes bad. I cannot read the characters. It's best when 1920X1080. I am not sure it is the limit of the graphics card or it is out of order. Should I change the graphics card for the higher res.? What would be recommended then?
Earlier Mac models