Well you could at least provide your specs, and "exactly the same" should also mean identical graphics cards and identically configured os and programs. Anyways regarding the dx9 files, i always install the complete dx9.0c package (which is 100ish mb in size), and never ever experienced any problems with performancetest, userbenchmark or any other testing utilities (dont know about 3dmark as i only used Vantage and FireStrike so far lol). With both amd and nvidia cards. (Geforce 8800GS, GT 310m, GT 640, GT 710, GTX 650Ti, GTX 460, GTX 580, GTX 680, GTX 960, GTX 1060 6GB, Radeon HD 4570, HD 5750, HD 6850, FirePro W5000, HD 7790 (r7 260x) HD 7970, RX 580 8g. Currently can test with 580 8gb in the main rig, and r7 260x in the office potato. I ve never seen the issue you are describing.