I'm playing on build 0.9.2 on a new map generated in this build. No Mods are used.
I have only a modest factory (just got automated smelting and an ugly setup for red/green going. When I start the game, Factorio grows to ~820MB mem util. After I load the map (attached) I get consistent memory increase along with graphical stutter every couple seconds (which seems to correspond with page fault frequency).
Video of process explorer performance graph for Factorio process after the game has been started. Game is running in the background without user input: http://screencast.com/t/u6CKXFkvi
Within about an hour or two memory utilization will grow to 5GB or so.
Edit:
Okay - I ran this through DebugDiag/DbgSvc with memory tracking for some time with immediate call stack recording turned on. Debugger was attached after the map was loaded. If you need I can send the full process dump, but it's several GB large. Otherwise I'm happy to help however else I can. One function address sort of sticks out in the report - offset 0x559027. In the call stack provided obviously ignore the LeakTrack at the top.
Further Edit: Over a 15-minute timeframe, I end up with ~765MBytes outstanding allocations from this offset.
Function details
Function Factorio+559027
Allocation type Heap allocation(s)
Heap handle 0x00000000`00000000
Allocation Count 1822541 allocation(s)
Allocation Size 249.19 MBytes
Leak Probability 95%
Top 10 allocation sizes by allocation count
48 Bytes - 1,045,219 allocation(s)
168 Bytes - 276,893 allocation(s)
16 Bytes - 112,898 allocation(s)
112 Bytes - 111,152 allocation(s)
464 Bytes - 111,151 allocation(s)
176 Bytes - 100,830 allocation(s)
40 Bytes -19,528 allocation(s)
360 Bytes - 18,422 allocation(s)
328 Bytes - 9,423 allocation(s)
8 Bytes - 8,044 allocation(s)
Top 10 allocation sizes by total size
2.08 MBytes - 64.36 MBytes
464 Bytes - 49.18 MBytes
48 Bytes - 47.85 MBytes
168 Bytes - 44.36 MBytes
176 Bytes - 16.92 MBytes
112 Bytes - 11.87 MBytes
360 Bytes - 6.32 MBytes
328 Bytes - 2.95 MBytes
16 Bytes - 1.72 MBytes
40 Bytes - 762.81 KBytes
Call stack sample 1
Address 0x00000001`4020be88
Allocation Time 00:00:05 since tracking started
Allocation Size 168 Bytes
Function Source Destination
LeakTrack+13277
Factorio+559027
Factorio+55abeb
Factorio+70cac
Factorio+21108f
Factorio+210ed6
Factorio+210ae0
Factorio+201acb
Factorio+2019d4
Factorio+201c1b
Factorio+bb06
Factorio+207bfa
Factorio+206fd2
Factorio+2092ec
Factorio+7661f
Factorio+201c78
Factorio+208573
Factorio+da995
Factorio+1939aa
Factorio+22e38a
Factorio+545223
Factorio+560073
Factorio+56021a
kernel32!BaseThreadInitThunk+d
ntdll!RtlUserThreadStart+1d