PC Graphics

[iam2quad]

i have a problem with my pc, i can't play fortnite with this lags, i have 40~100 fps but it always drops to 4~12, its unplayable, i try 16.2.1 beta driver and 15.7.1 whql, no difference. game was installed on SSD

all config:

CPU: Intel Core 2 Quad Q6600 @ 2.40 GHz ( 4 cores)
Video: AMD Radeon HD 5770 1024Mb
Mother: ASUS P5B Series
RAM: DDR2 Kingston 800 MHz 6GB
Monitor: Samsung SyncMaster 923nw (1440х900)
Power Supply: Aerocool VX-500 (500W)
HDD: Western Digital Blue 500GB / SSD Kingston 120GB
OC: Windows 10 LTSB 64 bit

[iam2quad]

hm, epic says: minimum requirements is i3 2.4ghz, 4gb ram and intel hd graphics 4000

but today, on all lowest settings in 720p, game eat 1800~mb vram and 6~7 gb ram, so, the question is closed

UPD: question not closed, why game runs perfectly with gtx 460? its to close to my 5770