IBM System x3750 M4 Express

Business use Ideal applications include high-performance computing, floating-point applications such as CAE and small to medium databases requiring fast I/O
Processor (Max) Up to two 8-core Intel Xeon E5-2600 series processors
Memory (Min/Max) Up to 1.5 TB via 48 slots with 32 GB LR-DIMM
Internal storage (Max) Up to 16 TB (2.5" HDD), 6.4 TB (1.8" eXFlash SSD)

IBM System x3650 M4 Express

Business use Ideal uses include your database, virtualization, ERP, collaboration, HPC, Cloud application, media streaming, on-line gaming, blog/wiki, messaging, web searching, transactional and file/print
Processor (Max) Up to two 8-core Intel Xeon E5-2600 series processors
Memory (Min/Max) Up to 768 GB via 24 slots (UDIMM/RDIMM/LRDIMM/HyperCloud DIMM)
 
Internal storage (Max) Up to 16 TB (2.5" model) or 18 TB (3.5" model) SAS/SATA HDDs

IBM System x3630 M4 Express

Business use Ideal applications include backup server, Web 2.0, imagery, video or photo sharing, online gaming, communication and collaboration (including blogs and messaging), file and print, mail server, transactional data, and web searching
Processor (Max) 2-, 4-, 6-, 8-core Intel Xeon processor E5-2400 product family, up to 1600 MHz memory access speed
Memory (Min/Max) Up to 384 GB DDR-3 RDIMM memory via 12 DIMM slots
Internal storage (Max) 4, 8 x 3.5-inch simple-swap SATA HDDs or 8 x 3.5-inch hot- swap SAS/SATA HDDs +tape (value model), 12+2x 3.5-inch hot-swap (storage-rich model)

IBM System x3550 M4 Express

Business use Ideal uses include your collaboration, Cloud application, media streaming, on-line gaming, blog/wiki, messaging, web searching, transactional, tile/print, database, virtualization and ERP
Processor (Max) Up to two 8-core Intel® Xeon® E5-2600 series processors
Memory (Min/Max) Up to 768 GB, 24 slots (UDIMM/RDIMM/LRDIMM)
Internal storage (Max) Up to 8 TB (2.5" models) or 9 TB (3.5" models) SAS/SATA

IBM System x3530 M4 Express

Business use Ideal applications include file & print, web serving, Web 2.0, virtualization, light database, ERP applications, small HPC install
Processor (Max) Up to two 8-core Intel Xeon E5-2400 series processors
Memory (Min/Max) Up to 384 GB via 12 slots UDIMM/RDIMM/LRDIMM
Internal storage (Max) Up to 8 TB SAS/SATA (2.5-inch model) or 12 TB SAS/SATA (3.5-inch model)

IBM System x3250 M5 Express

Business use Ideal applications include: Basic infrastructure, file, email and print, web serving and similar workloads
Processor (Max) Intel Xeon E3-1200 v3 series (quad-core) up to 3.6 GHz/8 MB/1600 MHz, Intel Core i3 series (dual-core) up to 3.6 GHz/4 MB/1600 MHz, Pentium series (dual-core) up to 3.3 GHz/3 MB/1600 MHz
Memory (Min/Max) 4 GB or 8 GB standard/up to 32 GB (UDIMM)
Internal storage (Max) Up to 12 TB

IBM System x3250 M4 Express

Business use Ideal applications include file and print, retail, network infrastructure and distributed applications
Processor (Max) Intel Xeon E3-1200v2 Series (quad-core) up to 3.6 GHz/8 MB/1600 MHz, Intel Core i3 2100 series (dual-core) up to 3.4 GHz/3 MB/1333 MHz, Pentium (dual-core) up to 3.0 GHz/3 MB/1333 MHz
Memory (Min/Max) Standard 1 × 4 GB 1600 MHz DDR-3 UDIMM, maximum 32 GB via four DIMM slots
Internal storage (Max) Up to 6.0 TB

IBM System x3500 M4 Express

Business use Ideal uses include your custom business applications, distributed branch applications, file sharing, email and collaboration, web services, departmental database, small-scale virtualization, enterprise resource planning (ERP), and customer relationship management (CRM)
Processor (Max) Up to two Intel Xeon Processor E5-2600 product family
Memory (Min/Max) Maximum 384 GB of DDR3 RDIMMs or 768 GB of DDR3 LRDIMMs or 64 GB of DDR3 UDIMMs, 24 DIMM slots maximum, up to 1600 MHz memory speed
Internal storage (Max) Up to 32 2.5" hot-swap and up to 32 TB (HDD upgrade options required) or eight 3.5" hot-swap or simple- swap drives up to 24 TB (via configure to order only)
 

IBM x3300 M4 Express

Business use Ideal applications include file and print, mail and collaboration, distributed office applications, and ERP applications
Processor (Max) Up to two Intel Xeon E5-2400 series processors
Memory (Min/Max) Up to 192 GB**, 12 slots (UDIMM/RDIMM)
** 32 GB LRDIMMs will be available in the first half of 2013 for a maximum capacity of 384 GB.
Internal storage (Max) 16 TB of 2.5-inch hot-swap SAS/SATA drives (HDD upgrade options required) or 24 TB of 3.5-inch hot-swap or simple-swap SAS/SATA HDDs
 

IBM System x3100 M4 Express

Business use Ideal applications include file and print, email and collaboration, firewall and small business applications
Processor (Max) Intel Xeon E3-1200v2 series (quad-core) up to 3.6 GHz/8 MB/1600 MHz, Intel Core i3 2100 series (dual-core) up to 3.4 GHz/3 MB/1333 MHz, Pentium (dual-core) up to 3.0 GHz/3 MB/1333 MHz and low-cost Celeron
Memory (Min/Max) 1 × 4 GB standard, maximum 32 GB 1600 MHz DDR-3 ECC UDIMMs via 4 DIMM slots
Internal storage (Max) 12.0 TB simple-swap Serial ATA hard disk drives

IBM System x3850 X5 Express

Business use Ideal applications include Enterprise applications such as ERP or CRM, small to medium databases and virtualization to support server consolidation
Processor (Max) Intel Xeon up to 2.4 GHz (10-core)/1066 MHz memory access
Memory (Min/Max) 32 GB/2.0 TB max PC3-10600 DDR3L, up to 3.0 TB with MAX5
Internal storage (Max) 4.8 TB per chassis (supports 8 × 73.4 GB, 146.8 GB, 300 GB, 500 GB and 600 GB SAS hard disk drives, 8 × 160 GB and 500 GB SATA hard disk drives, or 16 × 50 GB and 200 GB solid state drives)

IBM System x3690 X5 Express

Business use Ideal applications include Enterprise applications such as ERP or CRM databases and virtualization
Processor (Max) Eight-core Intel® Xeon® up to 2.27 GHz and 1066 MHz front-side bus, six-core Intel Xeon up to 2.0 GHz and 1066 MHz front-side bus, four-core Intel Xeon up to 1.86 GHz and 1066 MHz memory access
Memory (Min/Max) 2 GB, 4 GB, 8 GB, 16 GB/up to 512 GB max PC3-10600 DDR III with Advanced Buffer eXecution; 1.0 TB per chassis with MAX5
Internal storage (Max) 800 TB SAS per chassis (supports 73.4 GB, 146.8 GB, 300 GB, 500 GB hard disk drives)