When upgrading database servers, engineers often face the classic trade-off between memory capacity, memory speed, and CPU cores. Your current setup (2x Xeon 5335, 4GB RAM) is severely memory-constrained by modern standards. Let's analyze your options through the lens of database performance characteristics.

For most database workloads, memory size is king. The working set that fits in RAM dramatically reduces disk I/O. Consider these PostgreSQL configuration examples showing memory priorities:

# postgresql.conf memory allocation examples
shared_buffers = 25% of total RAM   # For 16GB: 4GB
effective_cache_size = 75% of RAM   # For 16GB: 12GB
work_mem = (total RAM / max_connections) # Example: 16GB/100 = 160MB

Your current 4GB is insufficient for any modern database. Among your options, the configurations with 16GB (Xeon 2620 and Xeon 3460) immediately stand out.

While memory capacity is primary, speed becomes important for:

• High-frequency random access patterns
• Large join operations that can't fit in CPU cache
• OLTP workloads with many concurrent transactions

The 1333MHz options provide roughly 2-2.5x the bandwidth of 533/667MHz, which matters when your working set exceeds CPU cache sizes.

Core count requirements depend on your query profile:

// Pseudocode showing parallel vs serial workload patterns
if (workload == "OLTP with many small transactions") {
    // Benefits from more cores
    optimal_cores = 8-16;
} else if (workload == "Analytics with large queries") {
    // Benefits from faster single-thread performance
    optimal_cores = 4-8 with higher clock speed;
}

The hex-core Xeon 2620 provides the best balance with 12 total cores at decent clock speeds.

While you're keeping the RAID 10 array, remember that more RAM reduces disk pressure. This MySQL example shows how memory affects disk I/O:

# Key MySQL memory parameters
innodb_buffer_pool_size = 12G  # For 16GB system
innodb_log_file_size = 2G      # For write-intensive workloads
query_cache_size = 1G          # If read-heavy

Based on typical database workloads, here's the priority order:

1. Memory size (16GB configurations preferred)
2. Memory speed (1333MHz over slower options)
3. Core count/architecture (modern hex-core beats older quads)
4. Cache sizes (handled automatically by CPU selection)

The Xeon 2620 (2x hex-core) with 16GB 1333MHz offers the best balance for most database workloads, providing both capacity and throughput.

When upgrading database hardware, we must first analyze the workload patterns. Most relational databases like MySQL, PostgreSQL, or SQL Server exhibit these characteristics:

// Typical database server resource usage pattern:
if (query_type == "OLTP") {
    memory_importance = HIGH;
    io_latency_sensitivity = HIGH;
    cpu_parallelism = MEDIUM;
} else if (query_type == "OLAP") {
    memory_importance = VERY_HIGH;
    cpu_parallelism = HIGH;
    io_throughput = HIGH;
}

For your current 4GB configuration, this is clearly the bottleneck. The optimal order should be:

1. Memory Size: Minimum 16GB for modern databases (your working set should fit in RAM)
2. Memory Speed: Faster RAM (1333MHz) improves cache coherency and reduces latency
3. Memory Channels: More channels (Dual/Quad-channel) increase bandwidth

Core count vs. clock speed depends on your specific workload:

# Example PostgreSQL configuration for different CPU architectures:
shared_buffers = 25% of RAM    # More important than CPU
effective_cache_size = 75% of RAM
work_mem = (RAM / max_connections) * 0.1

# For high-concurrency OLTP:
max_connections = 200
max_worker_processes = cores * 2

# For analytical workloads:
maintenance_work_mem = RAM / 16

While you're keeping the same RAID 10 configuration, consider these optimizations:

• Align filesystem blocks with RAID stripe size
• Separate transaction logs from data files physically
• Enable write-back caching if your controller supports battery backup

Given your options, I'd prioritize in this order:

1. 2x Xeon E5-2620 (hex core) + 16GB 1333MHz - Best balance
2. 1x Xeon E5-2650 (octo core) + 8GB 1333MHz - Good for parallel queries
3. 1x Xeon 3460 (quad core) + 16GB 1333MHz - Memory advantage

For MySQL on the recommended hardware:

[mysqld]
innodb_buffer_pool_size = 12G  # 75% of 16GB
innodb_log_file_size = 2G
innodb_flush_method = O_DIRECT
innodb_read_io_threads = 8
innodb_write_io_threads = 4
innodb_io_capacity = 2000
innodb_io_capacity_max = 4000