Memory upgrade for Dell Precision T7500

I am complete novice at computer upgrades - need to speed up my computer to run all Adobe products, AVS4You video software, surf multiple sites, currently my computer is taking sometimes ten minutes to load a file or program.

I am sure i need more ram but what type and how much and would the motherboard cope? or would i need to upgrade that too as well as the Processor?

My computer information according to Cpu-z
Processors
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Number of processors 1
Number of threads 6

APICs
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Processor 0
-- Core 0
-- Thread 0 0
-- Core 1
-- Thread 0 2
-- Core 2
-- Thread 0 4
-- Core 8
-- Thread 0 16
-- Core 9
-- Thread 0 18
-- Core 10
-- Thread 0 20

Timers
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ACPI timer 3.580 MHz
HPET timer 14.318 MHz
Perf timer 2.598 MHz
Sys timer 1.000 KHz


Processors Information
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Processor 1 ID = 0
Number of cores 6 (max 16)
Number of threads 6 (max 32)
Name Intel Xeon X5650
Codename Westmere-EP
Specification Intel(R) Xeon(R) CPU X5650 @ 2.67GHz
Package (platform ID) Socket 1366 LGA (0x0)
CPUID 6.C.2
Extended CPUID 6.2C
Core Stepping B1
Technology 32 nm
TDP Limit 95.0 Watts
Core Speed 3058.5 MHz
Multiplier x Bus Speed 23.0 x 133.0 MHz
Rated Bus speed 3191.5 MHz
Stock frequency 2666 MHz
Instructions sets MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, EM64T, VT-x, AES
L1 Data cache 6 x 32 KBytes, 8-way set associative, 64-byte line size
L1 Instruction cache 6 x 32 KBytes, 4-way set associative, 64-byte line size
L2 cache 6 x 256 KBytes, 8-way set associative, 64-byte line size
L3 cache 12 MBytes, 16-way set associative, 64-byte line size
FID/VID Control yes


Turbo Mode supported, enabled
Max turbo frequency 3066 MHz
Max non-turbo ratio 20x
Max turbo ratio 23x
Max efficiency ratio 12x
TDC Limit 95 Amps
Max bus number 63
# of QPI Links 2
Attached device PCI device at bus 63, device 2, function 0
Attached device PCI device at bus 63, device 2, function 4
Attached device PCI device at bus 63, device 3, function 4
Chipset
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Northbridge Intel 5520 rev. 22
Southbridge Intel 82801JR (ICH10R) rev. 00
Graphic Interface PCI-Express
PCI-E Link Width x4
PCI-E Max Link Width x16
Memory Type DDR3
Memory Size 3262 MBytes
Channels Triple
Memory Frequency 664.9 MHz (2:10)
CAS# latency (CL) 9.0
RAS# to CAS# delay (tRCD) 9
RAS# Precharge (tRP) 9
Cycle Time (tRAS) 24
Row Refresh Cycle Time (tRFC) 74
Command Rate (CR) 1T
Uncore Frequency 2659.6 MHz

Memory SPD
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Monitoring
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Mainboard Model 06FW8P (0x0000018B - 0x004A6A00)

LPCIO
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Hardware Monitors
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Hardware monitor NVIDIA I/O
Fan PWM 0 40 pc [0x28] (FANPWMIN0)

Hardware monitor NVIDIA NVAPI
Voltage 0 1.11 Volts [0x456] (VIN0)
Temperature 0 75°C (166°F) [0x4B] (TMPIN0)
Fan PWM 0 40 pc [0x28] (FANPWMIN0)

Hardware monitor NVIDIA NVAPI
Voltage 0 1.11 Volts [0x456] (VIN0)
Temperature 0 70°C (157°F) [0x46] (TMPIN0)