Turn explosions off and most of the lag should be gone.
This is my computer and I can't play with explosions enabled:
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System Information
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Time of this report: 9/7/2013, 21:03:37
Machine name: ĀµBERPWNER-HP
Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.130318-1533)
Language: Finnish (Regional Setting: Finnish)
System Manufacturer: Hewlett-Packard
System Model: HPE-316sc
BIOS: 05/19/10 14:28:47 Ver: 6.07
Processor: Intel(R) Core(TM) i5 CPU 650 @ 3.20GHz (4 CPUs), ~3.2GHz
Memory: 6144MB RAM
Available OS Memory: 6072MB RAM
Page File: 3059MB used, 9080MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 11
DX Setup Parameters: Not found
User DPI Setting: 96 DPI (100 percent)
System DPI Setting: 96 DPI (100 percent)
DWM DPI Scaling: Disabled
DxDiag Version: 6.01.7601.17514 32bit Unicode
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Display Devices
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Card name: ATI Radeon HD 5570
Manufacturer: Advanced Micro Devices, Inc.
Chip type: AMD Radeon Graphics Processor (0x68D9)
DAC type: Internal DAC(400MHz)
Device Key: Enum\PCI\VEN_1002&DEV_68D9&SUBSYS_6870103C&REV_00
Display Memory: 722 MB
Dedicated Memory: 2038 MB
Shared Memory: 2779 MB
Current Mode: 1280 x 1024 (32 bit) (60Hz)
Monitor Name: Generic PnP Monitor
Monitor Model: HP vs19
Monitor Id: HWP264C
Native Mode: 1280 x 1024(p) (60.020Hz)
Output Type: HD15
Driver Name: aticfx64.dll,aticfx64.dll,aticfx64.dll,aticfx32,aticfx32,aticfx32,atiumd64.dll,atidxx64.dll,atidxx64.dll,atiumdag,atidxx32,atidxx32,atiumdva,atiumd6a.cap,atitmm64.dll
Driver File Version: 8.17.0010.1172 (English)
Driver Version: 9.12.0.0
DDI Version: 11
Driver Model: WDDM 1.1
Driver Attributes: Final Retail
Driver Date/Size: 12/19/2012 23:08:04, 1151488 bytes