Quote Patriot (

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, I was wondering if Space engine uses more than 4gb of Vram to its advantage. I ask this because
Are you sure it have 8 Gb, but not 2 x 4 Gb? Because it have 2 chips in CrossFire mode, with their own VRAM, but it does not sum up. Second chip have a mirror copy of the VRAM content of the first chip. This is how CrossFire and SLI works.
Quote Patriot (

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While I'm asking questions is this game 64x or still 32x?
SE is 32 bit, but video memory usage is a deal of the driver, which may be 64 bit. Also, video memory is not the same as usual RAM, it is not addressed by CPU directly, so driver even could not be 32 bit to use more than 4 Gb of VRAM.
Quote Patriot (

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VideoMemoryStartupDetect false // detect size physical video memory (VRAM) at startup
VideoMemoryDynamicDetect false // detect available amount of video memory (VRAM) in runtime
VideoMemorySize 6144 // video memory size to use if VideoMemoryStartupDetect = false
If you want let SE use all available VRAM (and your driver is not buggy), just leave VideoMemoryStartupDetect true and VideoMemoryDynamicDetect true.
Quote DoctorOfSpace (

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No sense in setting it higher than 4096 since SE is a 32 bit program and will never use more than 4GBs.
This config setting is related only to VRAM, which is independent off RAM and 32/64 bit, as I said before.
However setting VRAM to 8 Gb (I believe there are no such graphics cards exist in reality) may make SE hit a 4 Gb RAM limit. Because some generated data is stored also into RAM, and memory manager takes into account both VRAM and RAM limits. This however have a little sense. The more data SE saves into memory cache, the more time is needed for memory manager to clean it up to free memory for the new data. This may result in lags and drop of FPS. SE 0.972 have a new limits for memory manager - number of terrain/star/galaxy nodes. With this limits, it never goes into 2 Gb of VRAM, and cleaning the memory cache is fast enough.
Quote the_nerervarine (

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unless you use 4gb patcher which I found hurts the stability of SE
This is needless, SE is built with 4Gb address aware since 0.96.