This is the same problem I fought against for over a YEAR. Any mods + 1070 was a nightmare to make work, and to make work with nice graphics. Others say it's no problem, that was NEVER my experience. BUT, finding someone who is well versed in 1070 B.S. to literally come in and help you with definitive results is so rare it's like tits on a bull - by the time it happens it is pretty much pointless. Years ago, I reinstalled GTAIV and stayed at Patch 1040 (Patch 4) / 1004 (Patch 5) and I've been happily seeking the "perfect" graphic mod since.
Texture pop ins are routinely caused by ENB's that are heavy on CPU. SSAO in your iceconfig.ini or enbseries.ini should be something like this, which will help avoid problems with CPU strain as well:
[SSAO_SSIL] ApplyAntialiasing=false SamplingQuality=0 // Use with ApplyAntialiasing=true SamplingRange=0 // Use with ApplyAntialiasing=true SizeScale=0.25 // higher = better looking, more defined SSAO effect, but costs a lot of fps. SourceTexturesScale=0.25 // higher = better looking, more defined SSAO effect, but costs a lot of fps. FilterQuality=0 // Filtering for SSAO, lower = higher quality filtering, higher = lower quality & more flickering. AOAmount=1.7 // Try 1.10 & 1.20. Always try to keep these two the same value, and try not to go higher than 1.50, or SSAO will look too bright. ILAmount=0.1 // Try 1.10 & 1.20. Always try to keep these two the same value, and try not to go higher than 1.50, or SSAO will look too bright. EdgeLighteningAmount=0.2 // This has a large affect when stood or parked under a light source, high values can make SSAO look extremely bright.
TIP: To avoid the whitish line under car tires with this type of SSAO setting set "SamplingRange=0" as above. For experimentation, go ahead and increase that distance in 1/4 increments (linear numbers) i.e.: 0.25