Samsung DDR2 SDRAM Computer 2 GB Capacity per Module RAM 2 Modules

Shop by Category

Computer Components & Parts

210 Results

Brand 4GB 2X2GB DDR2 2RX8 PC2-6400U 800MHz 240PIN DIMM Intel RAM Desktop memory
Brand New · Samsung
S$ 19.66
or Best Offer
S$ 34.63 shipping
4GB 2X 2GB Samsung 2RX8 PC2-6400 DDR2 800Mhz DIMM Desktop Memory Unbuffered RAM
Brand New · Samsung
S$ 44.87
or Best Offer
Free shipping
98 sold
Samsung 4GB KIT (2 x 2GB) Dell Optiplex 160 330 360 740 745 755 760 960 960D Ram
Brand New · Samsung
S$ 27.73
S$ 29.05 shipping
4GB KIT 2 x 2GB HP Compaq Business dc5800 dc5850 dc7800 dc7900 Ram Memory
Brand New · Samsung
S$ 23.54
or Best Offer
S$ 47.25 shipping
36 sold
Apple Mac 4GB Memory 2x 2GB 800MHz DDR2 PC2-6400 RAM for MacBook iMac 2008 2009
Brand New · Samsung
S$ 135.90
S$ 35.57 shipping
Only 1 left!
4GB (2x 2GB) Sony Vaio PCG 7111L/PCG 7112L/PCG 7113L//PCG 7141L/PCG 7142L Memory
Brand New · Samsung
S$ 25.21
S$ 28.98 shipping
3 watching
4GB (2 x 2GB) DDR2 667 ECC PC2 5300 DIMM for Dell Precision Workstation T3400
Brand New · Samsung
S$ 20.00
or Best Offer
S$ 28.83 shipping
Apple Mac 4GB Memory 2x 2GB 667MHz DDR2 PC2-5300 SODIMM RAM for MacBook Pro iMac
Brand New · Samsung
S$ 135.90
S$ 35.57 shipping
29 watching
Samsung 2x2GB 2Rx5 Pc-64000S-666-12-E3 Laptop RAM #SU-285
New (Other) · Samsung
S$ 24.70
S$ 15.54 shipping
41Y2732 4GB(2x2GB) DDR2-667 Memory IBM IntelliStation M Pro & more
Brand New · IBM
S$ 25.92
S$ 29.01 shipping
NQ605AT - HP 4-GB (2x2GB) PC2-6400 (DDR2 800 MHz) DIMM
Brand New · HP
S$ 35.11
or Best Offer
S$ 29.28 shipping
Only 1 left!
2 Samsung M378T2863DZS-CE6 1gb Ddr2 667mhz Pc2-5300 240pins READ DESCRIPTION
Brand New · Samsung
S$ 8.50
S$ 38.67 shipping
4GB KIT 2 x 2GB HP Compaq Business dc5800 dc5850 dc7800 dc7900 Ram Memory
Brand New · Samsung
S$ 28.16
S$ 29.07 shipping
Samsung 1GB 1Rx8 PC2-5300U Desktop Memory Ram M378T2863DZS-CE6 377726-888
Brand New · Samsung
S$ 28.07
or Best Offer
S$ 25.28 shipping
4GB 2x 2GB Kit Dell XPS M1210 M1330 M1530 M1710 M1730 M2010 DDR2 Laptop Memory
Brand New · Samsung
S$ 25.21
S$ 28.98 shipping
Apple Mac 2GB Memory 800MHz DDR2 PC2-6400 RAM for MacBook iMac 2008 2009 Core 2
Brand New · Samsung
S$ 72.05
S$ 35.57 shipping
Only 3 left
Apple Mac 2GB Memory 667MHz DDR2 PC2-5300 SODIMM RAM for MacBook Pro iMac Mini 2
Brand New · Samsung
S$ 68.40
S$ 35.57 shipping
10 watching
4GB 2x 2GB Kit HP Compaq 6710b 6715b 6715s 6735s 6820s 6830s 6910p DDR2 Memory
Brand New · Samsung
S$ 25.21
S$ 28.98 shipping
4GB 2x 2GB Kit HP Compaq 6735s 6820s 6830s 6910p 8510p 8510w 8710p 8710w Memory
Brand New · Samsung
S$ 25.21
S$ 28.98 shipping
Brand 4GB 2X2GB DDR2 2RX8 PC2-6400U 800MHz 240PIN DIMM Intel RAM Desktop memory
Pre-Owned · Samsung
S$ 18.24
S$ 28.77 shipping
88 sold
TOSHIBA Satellite P505 P505D L505 A505 A305 L305 L355D 4GB DDR2 Laptop Memory
Pre-Owned · Samsung
S$ 56.16
S$ 30.81 shipping
Only 1 left!
4GB DDR2 (2x 2GB) Laptop Memory for HP G60-237NR G60-235DX G60-549DX G60-530US
Pre-Owned · Samsung
S$ 49.13
S$ 30.60 shipping
4GB Kit DDR2 PC2-5300U Memory Upgrade for Dell Vostro 400 Desktop Computer / PC
Pre-Owned · Samsung
S$ 22.51
or Best Offer
S$ 22.51 shipping
2GB Samsung DDR2 M393T5750CZA-CE6 RAM 667MHz PC2-5300P ECC Reg CL5 2Rx4 Memory
Pre-Owned · Samsung
S$ 6.73
S$ 6.36 shipping
4GB Kit DDR2 Memory Upgrade RAM HP Compaq dc7900 SFF Non-ECC PC2-6400 800MHz
Pre-Owned · Samsung
S$ 28.14
or Best Offer
S$ 22.51 shipping
4GB Kit DDR2 Memory Upgrade RAM HP Compaq dc7600 Tower Non-ECC PC2-6400 800MHz
Pre-Owned · Samsung
S$ 20.63
or Best Offer
S$ 22.51 shipping
2GB Samsung DDR2-800 PC2-6400P CL5 ECC Reg RAM M393T5660QZA-CE7Q0 Server Memory
Pre-Owned · Samsung
S$ 13.61
S$ 6.04 shipping
4GB SAMSUNG 2 x 2GB PC2-6400 DDR2 800Mhz Desktop Memory Ram M378T5663EH3-CF7
Pre-Owned · Samsung
S$ 78.64
Free shipping
4GB Kit DDR2 Memory Upgrade Intel DP43TF Motherboard Non-ECC PC2-6400U 800MHz
Pre-Owned · Samsung
S$ 28.14
or Best Offer
S$ 22.51 shipping
4GB (2X2GB) DDR2-667 PC2-5300 ECC Register Samsung
Pre-Owned · Samsung
S$ 46.31
or Best Offer
S$ 29.60 shipping
4GB 2X 2GB Samsung 2RX8 PC2-6400 DDR2 800Mhz DIMM Desktop Memory Unbuffered RAM)
New (Other) · Samsung
S$ 45.05
or Best Offer
Free shipping
4GB DDR2 (2x 2GB) Laptop Memory for TOSHIBA Satellite L505D-LS5019 L505D-LS5010
Pre-Owned · Samsung
S$ 56.16
S$ 48.21 shipping
4GB DDR2 (2x 2GB) Laptop Memory for HP G60-120US G60-501NR G60-441US Notebooks
Pre-Owned · Samsung
S$ 49.12
S$ 30.60 shipping
4GB DDR2 (2x 2GB) Laptop Memory for TOSHIBA Satellite A215-S5837 A215-S5839
Pre-Owned · Samsung
S$ 42.11
S$ 43.01 shipping
Samsung 2x2GB DDR2 800MHz (TESTED on INTEL) - PC Memory
Pre-Owned · Samsung
S$ 11.23
or Best Offer
S$ 12.64 shipping
1GB Samsung DDR2-667 RAM PC2-5300U 1Rx8 M378T2863DZS-CE6 HP 377726-888
Pre-Owned · Samsung
S$ 4.61
S$ 6.48 shipping
4GB Kit (2 x 2GB) DDR2 Memory Upgrade for Acer Aspire X1301 PC2-5300U 667MHz RAM
Pre-Owned · Samsung
S$ 28.14
or Best Offer
S$ 18.75 shipping
4GB Kit DDR2 Memory Upgrade PC2-5300U 667MHz for Foxconn 45CMX-K Motherboard
Pre-Owned · Samsung
S$ 28.14
or Best Offer
S$ 22.51 shipping
4GB Kit DDR2 Memory Upgrade Gigabyte GA-EG41MF-US2H M/B Non-ECC PC2-6400U
Pre-Owned · Samsung
S$ 28.14
or Best Offer
S$ 22.51 shipping
RAM for Samsung NP-R700 - R700 Series - 2GB 2x1GB PC2-5300S DDR2 667MHZ
Pre-Owned · Samsung
S$ 16.21
or Best Offer
S$ 11.46 shipping
4GB Kit DDR2 Memory Upgrade Asus P5GC-MX/1333 Motherboard Non-ECC PC2-6400U
Pre-Owned · Samsung
S$ 28.14
or Best Offer
S$ 22.51 shipping
4GB Kit DDR2 Memory Upgrade PC2-6400U 800MHz for ASRock G31M-GS Motherboard
Pre-Owned · Samsung
S$ 28.14
or Best Offer
S$ 22.51 shipping
4GB Kit (2 x 2GB) Samsung M378T5663EH3-CF7 AB PC2-6400U DDR2 Computer Memory RAM
Pre-Owned · Samsung
S$ 22.51
or Best Offer
S$ 20.63 shipping
4GB DDR2 (2x 2GB) Laptop Memory for TOSHIBA L455-S5980 L455-S5981 L455-S5989
Pre-Owned · Samsung
S$ 42.11
S$ 30.39 shipping
4GB DDR2 (2GB x2) Laptop Memory for HP G60 G60-236US Compaq CQ60 CQ60-417DX
Pre-Owned · Samsung
S$ 42.11
S$ 29.49 shipping
4GB DDR2 (2x 2GB) RAM for HP Pavilion dv7-3079wm Entertainment Notebook PC
Pre-Owned · Samsung
S$ 56.16
S$ 48.21 shipping
6 watching
4GB DDR2 (2x 2GB) Laptop Memory for HP Compaq CQ60-210US CQ60-211DX CQ60-215DX
Pre-Owned · Samsung
S$ 42.11
S$ 29.49 shipping
4GB 2x 2GB Kit IBM/Lenovo Thinkpad R60/R60e/R61/R61e/T60/T60p/T61/X60/X61 Memory
Brand New · Samsung
S$ 75.96
Free shipping
4GB (2x2GB) DDR2 Upgrade for Intel DG41MJ Motherboard PC2-6400U Computer Memory
Pre-Owned · Samsung
S$ 24.39
or Best Offer
S$ 22.51 shipping
4GB Kit (2 x 2GB) DDR2 Memory Upgrade PC2-6400U 800MHz for Acer Aspire X1300 PC
Pre-Owned · Samsung
S$ 28.14
or Best Offer
S$ 22.51 shipping
4GB Kit (2 x 2GB) Samsung M378T5663QZ3-CF7 PC2-6400U DDR2 Computer Memory RAM
Pre-Owned · Samsung
S$ 18.75
or Best Offer
S$ 20.63 shipping
4GB Kit (2 x 2GB) DDR2 Memory Upgrade for Acer Aspire X1301 PC2-6400U 800MHz RAM
Pre-Owned · Samsung
S$ 24.39
or Best Offer
S$ 18.75 shipping
4GB SAMSUNG 2 x 2GB PC2-6400 DDR2 800Mhz Desktop Memory Ram M378T5663EH3-CF7
Pre-Owned · Samsung
S$ 81.03
Free shipping
4GB DDR2 (2x 2GB RAM) Laptop Memory for Toshiba P305 P305D-S8834 Notebook PC
Pre-Owned · Samsung
S$ 42.11
S$ 30.39 shipping
4GB DDR2 (2x 2GB) Laptop RAM for HP G60-633NR G60-440US G60-549DX G60-125NR CQ60
Pre-Owned · Samsung
S$ 56.16
S$ 48.21 shipping
Only 1 left!
4GB Kit DDR2 Memory Upgrade Gigabyte GA-P31-ES3G Motherboard Non-ECC PC2-5300U
Pre-Owned · Samsung
S$ 28.14
or Best Offer
S$ 22.51 shipping
4GB = 2X 2GB 2RX8 PC3-10600R DDR3-1333 128X8 18CHIPS 240PIN 43X5045 FRU: 44T1491
Pre-Owned · Samsung
S$ 25.26
S$ 28.98 shipping
Samsung 2GB 2Rx8 PC2-6400S-666-12-E3 DDR2 RAM 200 PIN SO DIMM M470T5663EH3-CF7
Pre-Owned · Samsung
S$ 14.03
or Best Offer
S$ 28.66 shipping
Only 1 left!
RAM for Asus F3 Series - F3S - 2GB 2x1GB PC2-6400S DDR2 800mhz Sodimm
Pre-Owned · Samsung
S$ 15.93
or Best Offer
S$ 11.18 shipping
4GB KIT 2 x 2GB HP Compaq Business dc5800 dc5850 dc7800 dc7900 Ram Memory
Brand New · Samsung
S$ 66.12
Free shipping
4GB 2X 2GB RAM MEMORY 4 HP Mini 110-1125LA, 110-1125NR 110-1100, 110-1105SL
New (Other) · Samsung
S$ 25.26
S$ 28.98 shipping
Samsung M470T5663EH3-CF7 4GB (2x2GB) PC2-6400 DDR2-800 SODIMM Laptop RAM
Pre-Owned · Samsung
S$ 21.51
or Best Offer
S$ 27.08 shipping
4GB 2x2GB PC2-6400 DDR2-800 SAMSUNG M378T5663EH3-CF7 Ram Memory HP 404575-888
Pre-Owned · Samsung
S$ 20.92
S$ 33.49 shipping
Samsung Crucial 4GB 2X 2GB DDR2 2RX8 PC2-6400U 800Mhz 240pin DIMM Desktop Memory
Pre-Owned · Samsung
S$ 23.17
S$ 28.93 shipping
Samsung 4GB KIT (2 x 2GB) Dell Optiplex 160 330 360 740 745 755 760 960 960D Ram
Brand New · Samsung
S$ 67.27
Free shipping
Samsung 2GB 2Rx8 PC2-6400S-666-12-E3 DDR2 RAM 200 PIN SO DIMM M470T5663EH3-CF7
Pre-Owned · Samsung
S$ 18.24
S$ 28.77 shipping
VTG SAMSUNG 2GBx2 2Rx8 Pc2 5300f-555-11-B0 For DELL PC GOOD
Pre-Owned · Samsung
S$ 23.55
or Best Offer
S$ 29.84 shipping
4GB Kit DDR2 Memory Upgrade Asus P5KPL-VM/V-P5G31/DP_MB Non-ECC PC2-6400U
Pre-Owned · Samsung
S$ 28.14
or Best Offer
S$ 22.51 shipping
3GB SET (2GB+1GB) SAMSUNG M378T5663QZ3-CF7 2RX8 PC2-6400U-666-12-E3 DDR2 PC RAM
Pre-Owned · Samsung
S$ 18.75
or Best Offer
S$ 24.39 shipping
4GB Kit DDR2 Memory Upgrade Intel DP35DP Motherboard Non-ECC PC2-5300U
Pre-Owned · Samsung
S$ 20.63
or Best Offer
S$ 22.51 shipping
4GB SAMSUNG 2 x 2GB PC2-6400 DDR2 800Mhz Desktop Memory Ram M378T5663EH3-CF7
Pre-Owned · Samsung
S$ 75.49
S$ 0.58 shipping
4GB DDR2 (2x 2GB) Laptop Memory for Dell Studio 1555 1557 1558 17 1735 Notebooks
Pre-Owned · Samsung
S$ 56.16
S$ 48.21 shipping
4GB DDR2 (2x 2GB) Laptop Memory for HP Compaq CQ60-615DX CQ60-211DX CQ60-210US
Pre-Owned · Samsung
S$ 56.16
S$ 48.21 shipping

Cameras & Photo

Collectibles

Computers & Tablets

Electronics

Fashion

Home & Garden

Jewelry & Watches

Toys & Hobbies

Other

Samsung DDR2 SDRAM Computer 2 GB Capacity per Module RAM 2 Modules

Shop by Category

210 Results

Brand 4GB 2X2GB DDR2 2RX8 PC2-6400U 800MHz 240PIN DIMM Intel RAM Desktop memory

4GB 2X 2GB Samsung 2RX8 PC2-6400 DDR2 800Mhz DIMM Desktop Memory Unbuffered RAM

Samsung 4GB KIT (2 x 2GB) Dell Optiplex 160 330 360 740 745 755 760 960 960D Ram

4GB KIT 2 x 2GB HP Compaq Business dc5800 dc5850 dc7800 dc7900 Ram Memory

Apple Mac 4GB Memory 2x 2GB 800MHz DDR2 PC2-6400 RAM for MacBook iMac 2008 2009

4GB (2x 2GB) Sony Vaio PCG 7111L/PCG 7112L/PCG 7113L//PCG 7141L/PCG 7142L Memory

4GB (2 x 2GB) DDR2 667 ECC PC2 5300 DIMM for Dell Precision Workstation T3400

Apple Mac 4GB Memory 2x 2GB 667MHz DDR2 PC2-5300 SODIMM RAM for MacBook Pro iMac

Samsung 2x2GB 2Rx5 Pc-64000S-666-12-E3 Laptop RAM #SU-285

41Y2732 4GB(2x2GB) DDR2-667 Memory IBM IntelliStation M Pro & more

NQ605AT - HP 4-GB (2x2GB) PC2-6400 (DDR2 800 MHz) DIMM

2 Samsung M378T2863DZS-CE6 1gb Ddr2 667mhz Pc2-5300 240pins READ DESCRIPTION

4GB KIT 2 x 2GB HP Compaq Business dc5800 dc5850 dc7800 dc7900 Ram Memory

Samsung 1GB 1Rx8 PC2-5300U Desktop Memory Ram M378T2863DZS-CE6 377726-888

4GB 2x 2GB Kit Dell XPS M1210 M1330 M1530 M1710 M1730 M2010 DDR2 Laptop Memory

Apple Mac 2GB Memory 800MHz DDR2 PC2-6400 RAM for MacBook iMac 2008 2009 Core 2

Apple Mac 2GB Memory 667MHz DDR2 PC2-5300 SODIMM RAM for MacBook Pro iMac Mini 2

4GB 2x 2GB Kit HP Compaq 6710b 6715b 6715s 6735s 6820s 6830s 6910p DDR2 Memory

4GB 2x 2GB Kit HP Compaq 6735s 6820s 6830s 6910p 8510p 8510w 8710p 8710w Memory

Brand 4GB 2X2GB DDR2 2RX8 PC2-6400U 800MHz 240PIN DIMM Intel RAM Desktop memory

TOSHIBA Satellite P505 P505D L505 A505 A305 L305 L355D 4GB DDR2 Laptop Memory

4GB DDR2 (2x 2GB) Laptop Memory for HP G60-237NR G60-235DX G60-549DX G60-530US

4GB Kit DDR2 PC2-5300U Memory Upgrade for Dell Vostro 400 Desktop Computer / PC

2GB Samsung DDR2 M393T5750CZA-CE6 RAM 667MHz PC2-5300P ECC Reg CL5 2Rx4 Memory

4GB Kit DDR2 Memory Upgrade RAM HP Compaq dc7900 SFF Non-ECC PC2-6400 800MHz

4GB Kit DDR2 Memory Upgrade RAM HP Compaq dc7600 Tower Non-ECC PC2-6400 800MHz

2GB Samsung DDR2-800 PC2-6400P CL5 ECC Reg RAM M393T5660QZA-CE7Q0 Server Memory

4GB SAMSUNG 2 x 2GB PC2-6400 DDR2 800Mhz Desktop Memory Ram M378T5663EH3-CF7

4GB Kit DDR2 Memory Upgrade Intel DP43TF Motherboard Non-ECC PC2-6400U 800MHz

4GB (2X2GB) DDR2-667 PC2-5300 ECC Register Samsung

4GB 2X 2GB Samsung 2RX8 PC2-6400 DDR2 800Mhz DIMM Desktop Memory Unbuffered RAM)

4GB DDR2 (2x 2GB) Laptop Memory for TOSHIBA Satellite L505D-LS5019 L505D-LS5010

4GB DDR2 (2x 2GB) Laptop Memory for HP G60-120US G60-501NR G60-441US Notebooks

4GB DDR2 (2x 2GB) Laptop Memory for TOSHIBA Satellite A215-S5837 A215-S5839

Samsung 2x2GB DDR2 800MHz (TESTED on INTEL) - PC Memory

1GB Samsung DDR2-667 RAM PC2-5300U 1Rx8 M378T2863DZS-CE6 HP 377726-888

4GB Kit (2 x 2GB) DDR2 Memory Upgrade for Acer Aspire X1301 PC2-5300U 667MHz RAM

4GB Kit DDR2 Memory Upgrade PC2-5300U 667MHz for Foxconn 45CMX-K Motherboard

4GB Kit DDR2 Memory Upgrade Gigabyte GA-EG41MF-US2H M/B Non-ECC PC2-6400U

RAM for Samsung NP-R700 - R700 Series - 2GB 2x1GB PC2-5300S DDR2 667MHZ

4GB Kit DDR2 Memory Upgrade Asus P5GC-MX/1333 Motherboard Non-ECC PC2-6400U

4GB Kit DDR2 Memory Upgrade PC2-6400U 800MHz for ASRock G31M-GS Motherboard

4GB Kit (2 x 2GB) Samsung M378T5663EH3-CF7 AB PC2-6400U DDR2 Computer Memory RAM

4GB DDR2 (2x 2GB) Laptop Memory for TOSHIBA L455-S5980 L455-S5981 L455-S5989

4GB DDR2 (2GB x2) Laptop Memory for HP G60 G60-236US Compaq CQ60 CQ60-417DX

4GB DDR2 (2x 2GB) RAM for HP Pavilion dv7-3079wm Entertainment Notebook PC

4GB DDR2 (2x 2GB) Laptop Memory for HP Compaq CQ60-210US CQ60-211DX CQ60-215DX

4GB 2x 2GB Kit IBM/Lenovo Thinkpad R60/R60e/R61/R61e/T60/T60p/T61/X60/X61 Memory

4GB (2x2GB) DDR2 Upgrade for Intel DG41MJ Motherboard PC2-6400U Computer Memory

4GB Kit (2 x 2GB) DDR2 Memory Upgrade PC2-6400U 800MHz for Acer Aspire X1300 PC

4GB Kit (2 x 2GB) Samsung M378T5663QZ3-CF7 PC2-6400U DDR2 Computer Memory RAM

4GB Kit (2 x 2GB) DDR2 Memory Upgrade for Acer Aspire X1301 PC2-6400U 800MHz RAM

4GB SAMSUNG 2 x 2GB PC2-6400 DDR2 800Mhz Desktop Memory Ram M378T5663EH3-CF7

4GB DDR2 (2x 2GB RAM) Laptop Memory for Toshiba P305 P305D-S8834 Notebook PC

4GB DDR2 (2x 2GB) Laptop RAM for HP G60-633NR G60-440US G60-549DX G60-125NR CQ60

4GB Kit DDR2 Memory Upgrade Gigabyte GA-P31-ES3G Motherboard Non-ECC PC2-5300U

4GB = 2X 2GB 2RX8 PC3-10600R DDR3-1333 128X8 18CHIPS 240PIN 43X5045 FRU: 44T1491

Samsung 2GB 2Rx8 PC2-6400S-666-12-E3 DDR2 RAM 200 PIN SO DIMM M470T5663EH3-CF7

RAM for Asus F3 Series - F3S - 2GB 2x1GB PC2-6400S DDR2 800mhz Sodimm

4GB KIT 2 x 2GB HP Compaq Business dc5800 dc5850 dc7800 dc7900 Ram Memory

4GB 2X 2GB RAM MEMORY 4 HP Mini 110-1125LA, 110-1125NR 110-1100, 110-1105SL

Samsung M470T5663EH3-CF7 4GB (2x2GB) PC2-6400 DDR2-800 SODIMM Laptop RAM

4GB 2x2GB PC2-6400 DDR2-800 SAMSUNG M378T5663EH3-CF7 Ram Memory HP 404575-888

Samsung Crucial 4GB 2X 2GB DDR2 2RX8 PC2-6400U 800Mhz 240pin DIMM Desktop Memory

Samsung 4GB KIT (2 x 2GB) Dell Optiplex 160 330 360 740 745 755 760 960 960D Ram

Samsung 2GB 2Rx8 PC2-6400S-666-12-E3 DDR2 RAM 200 PIN SO DIMM M470T5663EH3-CF7

VTG SAMSUNG 2GBx2 2Rx8 Pc2 5300f-555-11-B0 For DELL PC GOOD

4GB Kit DDR2 Memory Upgrade Asus P5KPL-VM/V-P5G31/DP_MB Non-ECC PC2-6400U