The only way to check this is by manually looking at your modules. However with a four slot machine like yours this is not an issue as you need to remove all of the existing ram to upgrade, but its worth knowing about.
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SSD 64GB 128GB 240GB 120GB 256GB 480GB 512GB 1TB 2TB 960GB Sata3 2.5 Hard Disk Disc 2.5 Internal Solid State Drive
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Originally from my IBM Thinkpad 755 back in the 1990's, then used in an HP Laserjet for 20 years.
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CORSAIR Vengeance LPX DDR3 Kit 8GB 2400MHz 2133MHz 1866MHz 1600MHz 1333MHz Desktop Memory 240Pin DIMM 1.5V DDR3 RAM
Aliexpress UK
We only supply branded memory such as Kingston, Hynix, Samsung, Micron, Crucial, Elpida, Integral etc. Please read the item specifics for more information on this product, if the title lists this as a kit, it will consist of the number of modules in the item specifics.8GB Kit (2x4GB) DDR3 Memory Upgrade for Dell OptiPlex 3010 7010 9010 PC3-10600U.
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B75 Motherboard Desktop M.2 LGA1155 For i3 i5 i7 CPU Supports DDR3 Memory SATA 3.0 USB 3.0 PEI-E VGA Interface Intel Core CPU
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Your PC has 2 Slots and can be upgraded to 16GB (2x8GB). INSIDE YOUR DELL OPTIPLEX 3040 - (MICRO PC). Kit Capacity: 16GB.
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JEYI Memory RAM Heatsink With Thermal Pads, Desktop RAM Cooler DDR Radiation Dissipate for PC DIY DDR2 DDR3 DDR4 DDR5
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Total Capacity: 32GB. INSIDE YOUR MAC PRO 2013. Your Mac Pro has 4 slots and the maximum possible upgrade is 128GB (4x32GB). Module Capacity: 16GB.
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Kllisre RAM DDR4 8GB 16GB Memory 2666MHz 3200MHz Desktop Dimm High Compatible
Aliexpress UK
Type: DDR4 DIMM. Latency: CL22. CL22 latency for stable multitasking. Exact timings: 22-22-22 (standard JEDEC for CL22). Speed: 3200MHz. 3200MHz speed for fast and responsive performance. Capacity: 8GB (Single Module).
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Orange Pi Zero 3 4GB RAM Allwinner H618 64-Bit WiFi 5 + BT5.0 LPDDR4 16MB SPI Flash Gigabit Ethernet Android 12 TV Ubuntu 22 OS
Aliexpress UK
Picture For Reference Purpose Only. Item Discription : .
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CRELANDER P8 Mini Laptop 8 Inch Touch Screen Intel Lake N150 12GB DDR5 WiFi 6 2 In 1 Laptop Notebook Tablet PC Pocket Laptop
Aliexpress UK
Don’t let sluggish performance hold you back! Compatible & Efficient. Total Capacity: 16 GB Number of Modules: 2 Form Factor: UDIMM Bus Speed: PC3L-12800 (DDR3L-1600). Superior Compatibility: Tested for compatibility with a variety of motherboards, ensuring strong performance and high stability.
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HUANANZHI B85 ITX Motherboard ITX Intel LGA 1150 i3 i5 i7 E3 DDR3 1600MHz 16GB M.2 SATA USB3.0 VGA DP HDMI-Compatible
Aliexpress UK